ELECTROMAGNETISM

MODUL • Fizik TINGKATAN 5

3 Keelektromagnetan

Electromagnetism

Objektif pembelajaran / Learning objective

• Menganalisis kesan magnet bagi konduktor yang membawa arus.
Analysing the magnetic effect of a current-carrying conductor.

• Memahami daya terhadap konduktor yang membawa arus dalam medan magnet.
Understanding the force on a current-carrying conductor in a magnetic field.

• Menganalisis aruhan elektromagnet.
Analysing electromagnetic induction.

• Menganalisis transformer.
Analysing transformer.

• Memahami penjanaan dan penghantaran elektrik.
Understanding the generation and transmission of electricity.

Kesan Magnet bagi Konduktor yang Membawa Arus UNIT 3
3.1 The Magnetic Effect of a Current-carrying Conductor

1 Perbandingan antara teras besi lembut dan teras keluli. Teras keluli
Comparison between soft iron core and steel core. Steel core

Teras besi lembut
Soft iron core

Mudah dimagnetkan dan dinyahmagnetkan Susah dimagnetkan dan dinyahmagnetkan
Difficult to be magnetised and demagnetised
Easily magnetised and demagnetised

Sesuai untuk menjadi magnet sementara Sesuai untuk menjadi magnet kekal
Suitable to be a temporary magnet (electromagnet) Suitable to be a permanent magnet

2 Terminologi Penerangan
Explanation
Terminology
Kawasan di mana bahan magnet mengalami daya
Medan magnet A region in which a magnetic material experiences a force
Magnetic field

Elektromagnet Magnet sementara yang diperbuat daripada gegelung wayar yang mengelilingi teras besi lembut
Electromagnet A temporary magnet made by a coil of wire round a soft iron core

79 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

3 Faktor-faktor yang mempengaruhi kekuatan medan magnet suatu elektromagnet.
Factors affecting the strength of the magnetic field of an electromagnet.

Faktor Penerangan
Factor Explanation

(a) Arus elektrik Apabila arus bertambah , kekuatan medan magnet bertambah.
Electric current , the strength of the magnetic field increases.
When the current increases

(b) Bilangan lilitan wayar Apabila bilangan lilitan wayar bertambah , maka kekuatan medan magnet bertambah.
Number of turns of wire When the number of turns of wire increases , the strength of the magnetic field increases.

(c) Jenis teras Teras yang berbeza mempunyai kekuatan medan magnet yang berbeza. Teras besi lembut
Type of material of core
mempunyai medan magnet yang paling kuat . Teras besi lembut boleh menumpukan
(d) Bentuk teras besi
The shape of the iron core garisan medan magnet yang melaluinya.

Different materials of the core have different strengths of magnetic field. Soft iron core has the

strongest magnetic field. A soft iron core is able to concentrate magnetic field lines

through it.

Teras besi berbentuk U mempunyai medan magnet yang lebih kuat daripada

teras besi yang lurus kerana teras besi berbentuk-U mempunyai dua kutub yang bertentangan

bersebelahan antara satu sama lain dan hasilnya garis medan magnet tertumpu dalam ruang di

antara dua kutub.

A U-shaped iron core has a stronger magnetic field than the straight iron core because

3UNIT U-shaped iron core has two opposite poles adjacent to each other and as a result the magnetic field

lines are concentrated in space between the poles.

Menentukan kutub hujung solenoid
Determining the poles of a solenoid

Lihat arah arus dari setiap hujung solenoid.
Jika arah arus mengikut arah jam, hujung solenoid itu ialah kutub selatan.
Jika arah arus mengikut arah lawan jam, hujungnya ialah kutub utara.
Look at the direction of the current from each end of the solenoid.
If the direction of the current is clockwise, the viewed end of the solenoid is the south pole.
If the direction of the current is anticlockwise, the viewed end is the north pole.

Arah ikut jam Arah lawan jam
Clockwise Anticlockwise

Kutub selatan Kutub utara
South pole North pole

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MODUL • Fizik TINGKATAN 5

4 Melukis corak medan magnet yang disebabkan oleh: Penyelesaian
Draw the pattern of the magnetic field due to: Solution

(a) Arus dalam wayar lurus
Current in a straight wire

(b) Arus dalam gegelung tunggal Penyelesaian
Current in a single coil Solution

UNIT 3

(c) Arus dalam solenoid Penyelesaian
Current in a solenoid Solution

N S

81 © Nilam Publication Sdn. Bhd.

UNIT 3 MODUL • Fizik TINGKATAN 5

© Nilam Publication Sdn. Bhd. Medan magnet Note / Nota:
Magnetic field Arah medan magnet yang mengelilingi wayar boleh ditentukan dengan
dua kaedah:
Produced by / Dihasilkan oleh The direction of the magnetic field around a wire can be determined using
Arus / Current two rules:

masuk / in Peraturan skru Maxwell / Maxwell’s screw rule

Wayar lurus Solenoid Gegelung Jika skru diputarkan, arah gerakannya sama arah
Straight wire Solenoid Coil dengan arah aliran arus, arah putarannya menentukan
arah medan magnet.
Kadbod tebal ditaburkan dengan serbuk besi Kadbod ditaburkan dengan serbuk besi Gegelung If a right-handed screws is turned so that it moves
Thick cardboard sprinkled with iron filings Cardboard sprinkled with iron filings Coil forwards in the same direction as a electric current, its
direction of rotation gives the direction of the magnetic
field due to the current.

Arah medan magnet
Magnetic field direction

Bekalan Kompas Solenoid N Arah arus +-
voltan memplot Solenoid
rendah Plotting
82 Low voltage compass Bekalan Direction of current Arah arus
supply voltan rendah Direction of current
Arus Garis medan Low-voltage
Current magnet S supply Hukum genggaman tangan kanan – Peraturan genggaman tangan kanan
Magnetic field untuk menentukan arah medan magnet
lines di kedua-dua gegelung The right-hand grip rule
Right-hand grip rule – to determine the
Hukum genggaman tangan kanan – Hukum genggaman tangan direction of magnetic field at both sides Arah medan magnet
untuk menentukan arah medan magnet kanan – untuk menentukan kutub of the coil Magnetic field direction
yang dihasilkan oleh arus dalam wayar solenoid
lurus Right-hand grip rule – to Arah arus
Right-hand grip rule – to determine the determine the poles of a solenoid Direction
direction of the magnetic field produced of current
by a current in a straight wire Ibu jari menunjukkan kutub utara
The thumb points to N pole Jika wayar yang membawa arus digenggam oleh
AGraahriasrumsedan magnet tangan kanan maka ibu jari menghala sepanjang dawai
DDiriercetciotinonofocf ucrurrernetn(tc(ocnovnevnetniotinoanla) l) menunjukkan arah arus dan jari yang lain menunjuk ke
arah medan magnet di sekeliling dawai.
AArarhahmmedeadnanmmagangentet Putaran jari mengikut arah arus If a wire carrying a current is gripped with the right
DDiriercetciotinonofomf magangenteicticfiefiledld Fingers curl in the direction of the current hand, the thumb points along the wire in the direction of
the current and the other fingers point in the direction of
the magnetic field around the wire.

(a) Corak medan magnet yang Solenoid digabungkan Arus mengalir keluar dari kertas Arus mengalir masuk ke dalam kertas
dihasilkan oleh konduktor dengan teras besi Current flows out of the paper Current flows into the paper
yang membawa arus lembut. Ia dipanggil:
bergantung kepada bentuk Combined with soft iron
konduktor. core. It is called:

The pattern of magnetic Elektromagnet
field produced by a current- An Electromagnet
carrying conductor depends
on the shape of the conductor Bekalan Suis ditutup Teras besi (a) Apabila dua wayar membawa arus yang sama dan dalam arah yang sama,
used. kuasa Closed Iron core kekuatan medan magnet paduan yang dihasilkan adalah dua kali ganda dan
a.t. switch corak yang dihasilkan adalah sama.
(b) Garis medan magnet yang
lebih padat antara satu sama d.c. Dawai When two wires are carrying the same current and in the same direction, the
lain menunjukkan medan power kuprum strength of the resultant magnetic field produced is doubled and the pattern is
magnet yang lebih kuat. the same.
supply bertebat
The magnetic field lines which
are closer to one another Insulated
represent a stronger magnetic copper
field. Pin lukisan wire
Drawing pin
(c) Garis medan magnet di
tengah adalah lebih padat (a) Apabila arus mengalir melalui gegelung, teras besi Kekuatan medan magnet bertambah dengan
antara satu sama lain The strength of the magnetic field is increased by:
disebabkan berhampiran lembut menjadi elektromagnet . (i) menggunakan arus yang lebih besar dalam gegelung.
When a current flows through the coil, the soft iron
dengan arus di tengah . using a bigger current through the coil.
The magnetic field lines in the core becomes an electromagnet .
middle are closer to one (b) Apabila arus dalam gegelung dihentikan, teras besi (ii) menambahkan bilangan lilitan gegelung
increasing the number of turns in the coil
another because they are lembut hilang kemagnetannya.
nearer to the current in When the current in the coil is switched off, the soft

the middle . iron core loses its magnetism.
(c) Kekuatan elektromagnet ini bergantung kepada:
The strength of the electromagnet depends on:
MODUL • Fizik TINGKATAN 5Aplikasi elektromagnetArah medan magnet dan
83 © Nilam Publication Sdn. Bhd. (i) Magnitud arus yang mengalir Applications of electromagnetism kompas memplot
Magnitude of current flow The direction of the magnetic field
(ii) Bilangan lilitan • Geganti elektromagnet and the plotting compass
Number of turns Electromagnetic relay
(iii) Jenis teras besi +
Type of iron core • Loceng elektrik -
(iv) Bentuk teras besi Electric Bell
The shape of the iron core Arah jarum kompas memplot
• Cuping telinga telefon menunjukkan arah medan magnet.
Telephone ear-piece The direction of the compass
needle indicates the direction of the
• Pemutus litar magnetic field.
Circuit breaker

3UNIT

MODUL • Fizik TINGKATAN 5

Eksperimen Untuk menentukan kekuatan elektromagnet
Experiment To determine the strength of an electromagnet

Inferens Mengkaji hubungan antara kekuatan Mengkaji hubungan antara kekuatan elektromagnet
Inference elektromagnet dengan arus dengan bilangan lilitan solenoid

To investigate the relationship between the strength of To investigate the relationship between the strength of an
an electromagnet and the current electromagnet and the number of turns of the solenoid

Kekuatan elektromagnet bergantung kepada Kekuatan elektromagnet bergantung pada bilangan lilitan

magnitud arus elektrik. solenoid.

The strength of an electromagnet depends on the The strength of an electromagnet depends on the number of

magnitude of the current. turns of solenoid.

3UNIT Hipotesis Kekuatan elektromagnet (berdasarkan bilangan Kekuatan elektormagnet (berdasarkan bilangan paku yang
Hypothesis paku yang terlekat kepada elektromagnet) terlekat kepada elektromagnet) bertambah apabila bilangan
bertambah apabila arus elektrik bertambah. lilitan solenoid bertambah.
Tujuan The strength of an electromagnet (indicated by the The strength of an electromagnet (indicated by the number
Aim number of nails attached to the electromagnet) of the nails attached to the electromagnet) increases as the
increases as the current increases. number of turns of solenoid increases.

Untuk mengkaji hubungan antara kekuatan Untuk mengkaji hubungan antara kekuatan elektromagnet
elektromagnet dan arus. dan bilangan lilitan solenoid.
To investigate the relationship between the strength of To investigate the relationship between the strength of an
an electromagnet and the current. electromagnet and the number of turns of solenoid.

Pemboleh Pemboleh ubah dimanipulasi: / Manipulated variable: Pemboleh ubah dimanipulasi: / Manipulated variable:
ubah Arus / Current Bilangan lilitan solenoid / The number of turns of solenoid
Variables
Pemboleh ubah bergerak balas: / Responding variable: Pemboleh ubah bergerak balas: / Responding variable:
Bilangan paku yang terlekat kepada elektromagnet Bilangan paku yang terlekat kepada elektromagnet
The number of nails attached to the electromagnet The number of nails attached to the electromagnet

Pemboleh ubah dimalarkan: / Constant variable: Pemboleh ubah dimalarkan: / Constant variable:
Bilangan lilitan solenoid, jenis teras Arus, jenis teras / Current, type of core
The number of turns of solenoid, type of the core

Senarai bahan Ammeter, wayar penyambung, reostat, kaki retort, Ammeter, wayar penyambung, reostat, kaki retort, suis,
dan radas suis, bekalan kuasa a.t., teras besi lembut, solenoid, bekalan kuasa a.t., teras besi lembut, solenoid, paku besi
List of paku besi kecil dan bekas plastik. kecil dan bekas plastik.
materials and Ammeter, connection wires, rheostat, retort stand, switch, Ammeter, connection wires, rheostat, retort stand, switch, d.c.
apparatus d.c. supply, soft iron core, solenoid, small iron nails and supply, soft iron core, solenoid, small iron nails and plastic
plastic container. container.

Susunan Teras besi Solenoid Teras besi Solenoid
radas lembut Solenoid lembut Solenoid
Arrangement Soft iron Soft iron
of the core } H Bekas core } H Bekas
apparatus plastik plastik
Paku besi Plastic Paku besi Plastic
kecil container kecil container
Small iron Small iron
nails nails

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MODUL • Fizik TINGKATAN 5

Prosedur 1. Suis ditutup. 1. Bilangan lilitan solenoid direkodkan, M = 5
Procedure The switch is closed. The number of turns of solenoid is recorded, M = 5

2. Bacaan ammeter direkodkan, l = 0.1 A 2. Hujung bawah solenoid ditetapkan pada jarak,
The reading of the ammeter is recorded, I = 0.1 A. H, dari bekas yang mengandungi paku besi.
The lower end of the solenoid is fixed at a height, H,
3. Hujung bawah solenoid ditetapkan pada jarak, from the container full of small iron nails.
H, dari bekas plastik yang mengandungi paku
besi kecil. 3. Bekas plastik dialihkan dan bilangan paku yang
The lower end of the solenoid is fixed at a height, H, tertarik kepada elektromagnet, N dikira dan dicatat.
from the plastic container full of small iron nails. The plastic container is removed and the number of
nails attached to the electromagnet, N is counted and
4. Bekas plastik dialihkan dan bilangan paku recorded.
yang terlekat kepada elektromagnet, N dikira
dan dicatatkan. 4. Eksperimen diulang dengan bilangan lilitan
The plastic container is removed and the number solenoid yang berbeza, M = 10, 15, 20, 25
of nails attached to the electromagnet, N are The experiment is repeated with different values of the
counted and recorded. number of turns of solenoid, M = 10, 15, 20, 25

5. Eksperimen diulang dengan nilai arus, yang UNIT 3
berbeza, I = 0.2 A, 0.3 A, 0.4 A dan 0.5 A
dengan melaraskan reostat.
The experiment is repeated with different values
of current, I = 0.2 A, 0.3 A, 0.4 A and 0.5 A by
adjusting the rheostat.

Arus, / Current, I / A 0.1 0.2 0.3 0.4 0.5 Bilangan lilitan, 5 10 15 20 25
Number of turns, M
Penjadualan Bilangan paku besi
data yang terlekat kepada Bilangan paku besi
Tabulation of yang terlekat kepada
data elektromagnet
Number of iron elektromagnet
nails attached to the Number of iron nails attached
electromagnet, N
to the electromagnet, N

Bilangan paku besi terlekat, N Bilangan paku besi terlekat, N
Number of iron nails attached, N Number of iron nails attached, N

Analisis data
Analysis of
the data

Arus, I / A Bilangan lilitan, M

0 Current, I / A 0 Number of turns, M

85 © Nilam Publication Sdn. Bhd.

UNIT 3 MODUL • Fizik TINGKATAN 5

© Nilam Publication Sdn. Bhd. APLIKASI ELEKTROMAGNET
APPLICATIONS OF ELECTROMAGNETS

86 1 Suis Geganti / Electromagnetic Relay 2 Loceng elektrik / Electric bell

Fungsi: Menghidupkan atau memutuskan litar sekunder yang mempunyai arus Cara kerja / Ways it works :
yang besar.
Function: To switch on or switch off the secondary circuit that has a large current. (i) Suis ditekan, arus mengalir melalui gegelung dawai.
Switch is pressed, the current flows through the coil wire.
Cara kerja / Ways it works :
(ii) Teras besi lembut dimagnetkan.
(i) Suis dihidupkan, arus mengalir melalui gegelung dawai. The soft iron core is magnetised.
The switch is on, current flows through the coil wire.
(iii) Angker besi lembut ditarik oleh teras besi lembut dan pengetuk mengetuk
(ii) Teras besi lembut dimagnetkan. loceng.
Soft iron core magnetised.
The soft iron armature is pulled by a soft iron core and hammer hit the bell.
(iii) Angker besi lembut ditarik oleh teras besi lembut.
Soft iron armature is pulled by a soft iron core. (iv) Litar terputus, teras besi lembut dinyah-magnetkan.
The circuit is cut off, then the soft iron core is demagnetised.
(iv) Sesentuh bersentuhan.
The contact touches. (v) Angker besi lembut kembali ke kedudukan asal dan litar dilengkapkan semula.
The soft iron armature restores to its original position and the circuit re-completed.
(v) Litar sekunder dihidupkan.
Secondary circuit is switched on. (vi) Proses ini berulang secara berterusan selagi suis masih ditekan.
The process is repeated continuously as long as the switch is pressed.

Bekalan voltan rendah Pivot / Pivot Bateri Suis tekan
Low voltage Battery Push switch
supply Armatur besi lembut bentuk L
L-shaped soft iron armature
X

Litar Y Spring sesentuh Spring
primer Spring contacts Springs
Primary
circuit Suis Kepingan besi Sesentuh
Switch lembut S Contacts
Soft iron yoke
Litar Teras besi lembut N Skru penyelaras sesentuh
sekunder Soft iron core Contact adjusting screw
Secondary
circuit Loceng / Bell Armatur besi lembut
Soft iron armature

Bateri kereta Motor 'pemula' Penukul / Hammer
Car battery Starter motor

3 Cuping telinga telefon / Telephone ear-piece 4 Pemutus litar / Circuit breaker

Cara kerja / Ways it works : Fungsi: Memutuskan bekalan kuasa apabila arus besar mengalir melalui litar.
Function: To disconnect the power supply when there is too large current flowing through
(i) Semasa bercakap melalui mikrofon, tenaga bunyi ditukar kepada tenaga a circuit.
elektrik.
Cara kerja / Ways it works :
While talking through the microphone, the sound energy is converted into electrical
energy. (i) Semasa berlaku litar pintas, arus bertambah secara tiba-tiba.
During the short circuit occurs, the current increases suddenly.
(ii) Arus elektrik yang berubah-ubah mengalir melalui gegelung dawai di cuping
telinga. (ii) Kekuatan elektromagnet bertambah sehingga mencukupi untuk menarik angker
besi lembut.
The varying current flowing through the coil wire at the earpiece.
The strength of electromagnet increases until it is sufficient to pull the soft iron
(iii) Teras besi lembut dimagnetkan dengan kekuatan yang berubah-ubah. armature.
The soft iron core is magnetised with varies strength.
(iii) Apabila sentuhan di sesentuh terpisah dan litar terputus, arus berhenti mengalir.
(iv) Diafragma ditarik oleh teras besi lembut dengan daya yang berubah-ubah. When the contact switch disconnected and the circuit is switched off, the current stop
The diaphragm is pulled by soft iron core with varies force.
flowing.
(v) Diafragma bergetar, molekul-molekul udara dimampat dan direnggangkan
secara berselang seli.

The diaphragm vibrates, molecules of air is compressed and rarefied alternately.

(vi) Tenaga dipindahkan ke telinga pendengar.
Energy is transferred to the listener's ears

(vii) Tenaga bunyi yang dihasilkan mempunyai frekuensi yang sama dengan
frekuensi bunyi yang asal.

The sound energy is produced with the same frequency as the original sound.

Solenoid
Solenoid

Magnet kekal
Permanent magnet

Arus mengalir dari mikrofon
Current flows from microphone

Teras besi lembut
Soft iron pole piece

Diafragma aloi bermagnet
Magnetic alloy diaphragm
MODUL • Fizik TINGKATAN 5SesentuhAngker besi lembut
87 © Nilam Publication Sdn. Bhd. Contacts Soft iron armature

Ke litar rumah Elektromagnet
To household S N Electromagnet
circuit
Wayar hidup
Live Wire

Pangsi berspring, P
Pivot with spring, P

Spring, Q

Butang reset
Reset button

3UNIT

MODUL • Fizik TINGKATAN 5

Teknik Menjawab [Format Kertas 2 : Bahagian B]
Answering Technique [Paper 2 Format : Part B]

Rajah menunjukkan satu loceng elektrik. Apabila suis dihidupkan, loceng berdering berterusan tetapi menghasilkan bunyi yang
lemah. / Diagram shows an electric bell. When the switch is on, the bell rings continuously but produces weak sound.

Suis Bateri 12 V
Switch 12 V Battery

Lilitan / Turns Spring / Spring Cadang dan terangkan pengubahsuaian yang perlu dibuat untuk
Teras / Core menghasilkan satu loceng elektrik yang bunyinya kuat.
Sesentuh / Contacts Suggest and explain modifications that should be made to produce
Penukul / Hammer a loud electric bell.
Gong / Gong
[10 markah / marks]

Cadangan / Suggestion Sebab / Reason

Jenis bahan gegelung dawai: / Type of material of coil wire:

3UNIT Kuprum Rintangan lebih rendah

Copper [M1] Lower resistance [M2]

Bilangan lilitan gegelung dawai: / Number of turns of coil wire:

Lebih banyak Daya elektromagnet lebih besar

More [M3] Larger electomagnetic force [M4]

Diameter gegelung dawai: / Diameter of coil wire:

Lebih besar Rintangan lebih rendah

Larger [M5] Lower resistance [M6]

Saiz gong: / Size of gong: • Memindahkan lebih banyak tenaga / More energy transferred [M8]
Lebih besar [M7] • Bilangan molekul udara lebih banyak / More number of air molecules
Larger

Pemalar spring: / Spring constant: Spring lebih kenyal untuk memukul gong dengan daya yang kuat [M10]
Lebih besar [M9] Spring is more elastic to hit the gong with bigger force
Larger

Reka bentuk teras: / Design of the core: Daya elektromagnet lebih kuat [M12]
Bentuk U (atau tunjuk dengan lukisan) [M11] Larger electromagnetic force
U-shaped (or shows the drawing)

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MODUL • Fizik TINGKATAN 5

Latihan / Exercise

1 Rajah (a) dan Rajah (b) menunjukkan susunan radas bagi mengkaji hubungan antara bilangan lilitan gegelung dawai dengan
kekuatan medan magnet di sekeliling dawai. / Diagram (a) and Diagram (b) show the set-up of the apparatus to study the relationship
between the numbers of turns of the wire coil with the strength of the magnetic field around the wire.

Gegelung dawai Gegelung dawai
Wire coil Wire coil
Kadbod
Cardboard Kadbod
Cardboard

Corak serbuk
besi
Iron powder
pattern

Ammeter Ammeter
Ammeter Ammeter

Ke bekalan kuasa a.t Ke bekalan kuasa a.t
To d.c power supply To d.c power supply

Rajah (a) / Diagram (a) Rajah (b) / Diagram (b)

(a) Perhatikan Rajah (a) dan Rajah (b) dengan teliti. Lengkapkan jadual di bawah dengan membandingkan aspek-aspek yang UNIT 3
dinyatakan. / Observe the Diagram (a) and Diagram (b) carefully. Complete the table below by comparing the aspects mentioned.

Aspek / Aspect Rajah (a) / Diagram (a) Rajah (b) / Diagram (b)
Sama / Same Sama / Same
Bacaan ammeter
The reading of ammeter

Magnitud arus Sama / Same Sama / Same
The magnitude of current

Bilangan lilitan gegelung dawai Banyak / More Kurang / Less
The number of turns of coil wire

Susunan corak serbuk besi Lebih rapat / Closer Kurang rapat / Less closer
The arrangement pattern of iron powder

Kekuatan medan magnet di sekeliling gegelung dawai Lebih kuat / Stronger Kurang kuat / Less stronger
The strength of the magnetic field around the coil wire

(b) Seterusnya, hubung kaitkan bilangan lilitan gegelung dawai dan kekuatan medan magnet di sekeliling dawai.
Hence, relate the number of turns of coil wire and the strength of magnetic field around the wire.
Bilangan lilitan gegelung dawai semakin bertambah, kekuatan medan magnet di sekeliling dawai semakin bertambah.

As the number of turns of coil wire increases, the strength of magnetic field around the wire increases.

(c) Seterusnya, deduksikan konsep fizik yang dapat menerangkan pembentukan susunan corak serbuk besi di Rajah (a) dan
Rajah (b). / Hence, deduce the physics concept to explain the formation of the arrangement pattern of iron filings in Diagram
(a) and Diagram (b).

Elektromagnet / Electromagnet

(d) Pemboleh ubah / Variables:
(i) Dimanipulasikan / Manipulated : Bilangan lilitan gegelung dawai / Number of turns of coil wire
(ii) Bergerak balas / Responding : Kekuatan medan elektromagnet / Strength of electromagnet
(iii) Dimalarkan / Constant : Arus elektrik / Current

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MODUL • Fizik TINGKATAN 5

2 Rajah (a) dan Rajah (b) menunjukkan susunan radas bagi mengkaji hubungan antara bilangan lilitan gegelung dawai dengan
kekuatan medan magnet di sekeliling dawai. / Diagram (a) and Diagram (b) show the set-up of the apparatus to study the relationship
between the numbers of turns of the wire coil with the strength of the magnetic field around the wire.

50 kg besi buruk dinaikkan 100 kg besi buruk dinaikkan
50 kg scrap metal is lifted 100 kg scrap metal is lifted

Kabel Kren Kabel
Cable Crane Cable

Kren 20 A
Crane
Solenoid Besi buruk
Besi buruk Solenoid Scrap metal
Scrap metal

Rajah (a) / Diagram (a) Rajah (b) / Diagram (b)

(a) Perhatikan Rajah (a) dan Rajah (b) dengan teliti. Lengkapkan jadual di bawah dengan membandingkan aspek-aspek yang
dinyatakan. / Observe the Diagram (a) and Diagram (b) carefully. Complete the table below by comparing the aspects mentioned.

Aspek / Aspect Rajah (a) / Diagram (a) Rajah (b) / Diagram (b)

3UNIT Jisim besi buruk yang dinaikkan Kurang / Less Lebih / More
The mass of scrap metal lifted

Kekuatan medan elektromagnet yang terhasil Kurang / Less Lebih / More
The strength of electromagnetic field produced

Arus elektrik yang mengalir melalui kabel Kurang / Less Lebih / More
Current flowing throught the cable

(b) Seterusnya, hubung kaitkan: / Hence, relate:
(i) arus elektrik yang mengalir melalui kabel dan jisim besi buruk yang dinaikkan.
the current flowing through the cable and the mass of scrap metal lifted.

Arus elektrik yang mengalir melalui kabel semakin bertambah, jisim besi buruk yang dinaikkan semakin

bertambah atau sebaliknya.

As the current flowing through the cable increases, the mass of scrap metal lifted increases or vice versa.

(ii) arus elektrik yang mengalir melalui kabel dan kekuatan medan magnet yang terhasil.
the current flowing through the cable and the strength of magnetic field produced.

Arus elektrik yang mengalir melalui kabel semakin bertambah, kekuatan medan magnet yang terhasil

semakin bertambah atau sebaliknya

As the current flowing through the cable increases, the strength of magnetic field produced increases or vice versa.

(c) Seterusnya, deduksikan konsep fizik yang dapat menerangkan situasi-situasi di Rajah (a) dan Rajah (b).
Hence, deduce the physics concept to explain the situations di Diagram (a) and Diagram (b).

Elektromagnet / Electromagnet

(d) Pemboleh ubah / Variables:
(i) Dimanipulasikan / Manipulated: Arus elektrik / Current
(ii) Bergerak balas / Responding: Kekuatan medan elektromagnet / Strength of electromagnet
(iii) Dimalarkan / Constant : Bilangan lilitan gegelung dawai pada teras besi lembut
The number of turns of wire coil on the soft iron core

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MODUL • Fizik TINGKATAN 5

Daya pada Konduktor Pembawa Arus dalam Satu Medan Magnet
3.2 The Force on a Current-Carrying Conductor in a Magnetic Field

Daya magnet Nota/Note:
Magnetic force Arah daya magnet boleh

Apabila berlaku saling tindakan When there is interaction ditentukan menggunakan
antara dua medan magnet between the two magnetic fields peraturan tangan kiri Fleming.
Direction of the magnetic force can

be determined by using Fleming’s

Medan magnet dihasilkan Menghasilkan Medan magnet oleh left-hand rule.
oleh konduktor yang Produced magnet kekal
membawa arus Magnetic field of the Arah daya, F
Direction of Force, F

Magnetic field produced by Medan magnet paduan permanent magnets

current carrying conductor dipanggil medan lastik Arah medan
Resultant magnetic field is magnet, B
S Direction
called catapult field of Magnetic

Daya yang dihasilkan Medan N field, B
menolak wayar ke magnet
kanan disebabkan Arah arus, I
Force produced pushes oleh magnet Direction of
the wire to the right magnadur Current, I
Magnetic
S field due to
magnadur
Corak medan magnet: Medan F magnets
Pattern of magnetic field: kuat
(a) bulatan sepusat Strong N UNIT 3
field

concentric circles Magnet magnadur (kutub selatan) Corak medan magnet:
(b) garis medan magnet Magnadur magnet (south pole) Pattern of magnetic field:
(a) medan magnet seragam di bahagian tengah
yang berdekatan Besi Wayar kuprum
dengan konduktor bentuk Uniform magnetic field in the middle
rapat antara satu sama U Copper wire
lain Iron (b) medan magnet yang tidak seragam di tepi
magnetic field lines yoke F Bekalan kuasa Non-uniform magnetic field at the side
nearer to the conductor voltan rendah,
are closer to one
another arus tinggi

B Low-voltage
N
Kayu high-current
penahan power supply

Wooden

Magnet magnadur support

Magnadur magnet

Kekuatan medan magnet Wayar kuprum / Copper wire
bergantung pada: / The strength (a) Saling tindakan di antara medan magnet yang dihasilkan oleh arus elektrik
of the magnetic field depends on:
dan medan magnet oleh magnet magnadur menghasilkan daya magnet.
Nilai arus yang mengalir The interaction between the magnetic field produced by the current and the
Magnitude of the current
magnetic field of the magnadur magnet produces a magnetic force.
Arus boleh ditingkatkan dengan: (b) Daya magnet bertindak ke atas wayar kuprum.
The current can be increased by: The magnetic force exerts on the copper wire.
(a) menambahkan d.g.e bekalan kuasa. (c) Wayar kuprum bergerak ke kanan.
The copper wire moves to the right.
increasing the e.m.f. of the power
supply. Kekuatan medan magnet boleh ditingkatkan dengan:
A stronger magnetic field can be produced by:
(b) menggunakan wayar sama panjang
yang lebih tebal. (a) menggunakan magnet yang lebih kuat. / using more powerful magnets.
(b) menggunakan dua kepingan magnet dengan kutub yang sama bersebelahan.
using a thicker wire of the same using two pairs of magnets with like poles side by side.
length. (c) meletakkan magnet berdekatan antara satu sama lain untuk mengurangkan jarak

(c) menggunakan wayar yang antara kedua-dua kutub magnet itu. / placing the magnets closer to each other to
lebih pendek. narrow the gap between the poles of the magnet.
using a shorter wire.

91 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5 Penerangan Video
Explanation
Terminologi Elektromagnet
Terminology Satu daya yang dikenakan ke atas konduktor yang Electromagnetic
Daya magnet membawa arus dalam medan magnet. https://goo.gl/GiJsmA
Magnetic force A force exerted on a conductor that carries a current in
a magnetic field.
Medan lastik
(Medan magnet paduan) Medan magnet paduan yang dihasilkan oleh saling
Catapult Field tindakan antara medan magnet yang dihasilkan oleh
(Resultant magnetic field) arus dan medan magnet oleh magnet kekal.
Is the resultant magnetic field produced by interaction
between the magnetic field produced by current and
magnetic field of the permanent magnet.

Eksperimen (1) Eksperimen untuk menentukan magnitud daya saling tindakan atas konduktor pembawa
Experiment arus dalam medan magnet kekal / An experiment to determine the magnitude of the catapult
force on a current-carrying conductor in a permanent magnetic field
3UNIT
(2) Hubungan antara magnitud arus yang mengalir dalam konduktor dan magnitud daya
yang bertindak ke atasnya / Relationship between magnitude of the current flowing in the
conductor and the magnitude of the force acting on it

Inferens Magnitud daya pada konduktor membawa arus dalam Magnitud daya yang bertindak ke atas suatu
Inference medan magnet bergantung kepada magnitud arus konduktor bergantung kepada magnitud arus yang
yang mengalir. mengalir dalam konduktor.
Hipotesis The magnitude of the force on a current-carrying Magnitude of the force acting on a conductor depends
Hypothesis conductor in a magnetic field depends on the magnitude on the magnitude of the current flowing in the
of the current. conductor.
Tujuan
Aim Magnitud daya pada konduktor yang membawa Apabila arus yang mengalir dalam konduktor
arus dalam medan magnet bertambah (ditentukan meningkat, magnitud daya yang bertindak
oleh jarak gerakan wayar kuprum pendek) apabila meningkat.
magnitud arus yang mengalir bertambah (ditentukan When the current flowing in the conductor is increases,
oleh magnitud beza keupayaan, V). the magnitude of the force acting on it increases.
The magnitude of the force on a current-carrying
conductor in a magnetic field (indicated by the distance
of movement of short copper wire) increases as the
magnitude of the current increases (indicated by
magnitude of potential difference, V).

Mengkaji hubungan antara magnitud daya pada Untuk mengkaji hubungan antara arus yang mengalir
konduktor yang membawa arus dalam medan magnet dalam konduktor dan daya yang bertindak ke atas
dengan magnitud arus yang mengalir. konduktor.
To investigate the relationship between the magnitude of To investigate the relationship between the current
the force on a current-carrying conductor in a magnetic flowing in the conductor and the force acting on the
field with the magnitude of the current. conductor.

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MODUL • Fizik TINGKATAN 5

Pemboleh ubah Pemboleh ubah dimanipulasikan: Pemboleh ubah dimanipulasikan:
Variables Manipulated variable: Manipulated variable:
Arus yang mengalir dalam konduktor
Senarai radas Magnitud beza keupayaan, V. Current flowing in the conductor
dan bahan Pemboleh ubah bergerak balas: / Responding variable:
List of apparatus Magnitude of the potential difference, V. Magnitud daya yang bertindak ke atas konduktor
and materials Pemboleh ubah bergerak balas: (ditentukan oleh kelajuan gerakan konduktor)
Responding variable: Magnitude of the force acting on the conductor (indicated
Susunan radas
Arrangement of the Jarak gerakan wayar kuprum pendek, L. by the speed of movement of the thin copper wire)
apparatus Pemboleh ubah yang dimalarkan: / Constant variable:
Distance of movement of short wire, L. Kekuatan medan magnet
Pemboleh ubah yang dimalarkan: The strength of the magnetic field
Constant variable:

Kekuatan medan magnet kekal

The strength of the permanent magnetic field

Magnet magnadur, dening besi berbentuk U, wayar Magnet magnadur, dening besi berbentuk U, blok
kuprum yang tebal, wayar kuprum pendek, bekalan kayu, pita pelekat, reostat, bekalan kuasa a.t, rod
kuasa a.t. (arus terus) dan pembaris kuprum nipis, wayar kuprum dan ammeter.
Magnadur magnet, U-shaped iron yoke, wooden block,
adhesive tape, rheostat, d.c. power supply, thin copper
rod, copper wire and ammeter.

Dening besi Wayar kuprum Dening besi UNIT 3
berbentuk U pendek Iron yoke
U-shaped Short copper wire
iron yoke Magnet magnadur Bekalan kuasa a.t
Wayar kuprum tebal
Thick copper wire Magnadur magnet a.c power supply
Pita pelekat

Adhesive tape

Rod kuprum nipis Ammeter
Thin copper rod Ammeter

Blok kayu A
Wooden block
Reostat
Magnet magnadur Bekalan kuasa a.t. Rheostate
Magnadur magnet d.c. power supply
Wayar kuprum
Copper wire

1 Voltan bekalan kuasa a.t. yang digunakan 1 Radas disediakan seperti yang ditunjukkan dalam

dicatatkan; V = 1.5 V. Bekalan kuasa a.t. rajah di atas.

dihidupkan. The apparatus is set up as shown in the diagram

The voltage of the d.c. power supply used is recorded; above.

V = 1.5 V. The d.c. power supply is switched on. 2 Dua magnet magnadur diletakkan pada dening

2 Jarak gerakan wayar kuprum pendek di atas besi berbentuk U dengan kutub bertentangan

wayar kuprum tebal diukur dengan pembaris = L. menghadap satu sama lain.

The distance of movement of short copper wire on the Two magnadur magnets are placed on the U shaped

Prosedur thick copper wire is measured by a ruler = L. iron yoke with opposite poles facing each other.
Procedure
3 Eksperimen diulangi dengan bekalan beza 3 Arus dihidupkan dan reostat dilaraskan kepada

keupayaan, V = 2.0 V, 2.5 V, 3.0 V dan 3.5 V. arus rendah 0.1 A.

The experiment is repeated with different voltages of The current is switched on and the rheostat is

d.c. power supply, V = 2.0 V, 2.5 V, 3.0 V and 3.5 V. adjusted to the low current 0.1 A.

4 Pergerakan rod kuprum nipis diperhatikan.

The movement of the thin copper rod is observed.

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MODUL • Fizik TINGKATAN 5

5 Langkah 3 dan langkah 4 diulang dengan
melaraskan rheostat pada arus 0.2 A, 0.3 A
dan 0.4 A.

Step 3 and step 4 are repeated with current 0.2 A,
0.3 A and 0.4 A by adjusting the rheostat.
6 Semua keputusan dicatatkan.
All the results are recorded.

Beza keupayaan Jarak gerakan wayar I (A) Pergerakan rod kuprum nipis
Potential difference, Distance of movement, Movement of thin copper rod
0.1
V/V L / cm 0.2
1.5 0.3
Penjadualan data 0.4
Tabulation of the 2.0
data
2.5
Menganalisis data
Analysis of the data 3.0

3.5

3UNIT Jarak gerakan, Jarak gerakan,
Distance of movement, Distance of movement,
L / cm L / cm

Beza keupayaan,

0 Potential difference, 0 I/A
V/V

Aplikasi daya saling tindakan pada konduktor yang membawa arus dalam satu medan magnet kekal
Applications of a force on a current-carrying conductor in a permanent magnetic field

Jenis Motor arus terus Meter gegelung bergerak (ammeter atau voltmeter)
Type Direct current motor Moving-coil meters (ammeter or voltmeter)

Rajah Gegelung Penunjuk Skala
Diagram Coil Pointer
Magnet kekal Scale
Permanent Berus karbon
magnet Carbon brush Magnet Spring pengawal
kekal Control spring
Berus karbon Permanent
Carbon brush magnet Arus
Komutator keluar
Commutator Current out

Bateri Gegelung Arus
Battery masuk
kuprum Silinder Bearing Current
Copper coil besi Bearing in

lembut

Soft iron

cylinder

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MODUL • Fizik TINGKATAN 5

Kawasan medan magnet lemah Kawasan medan magnet kuat
Weak magnetic field region Strong magnetic field region

Bentuk
medan lastik
Pattern of
catapult field

(a) Saling tindakan antara medan magnet yang dihasilkan oleh (a) Ia terdiri daripada gegelung kuprum segi
arus dan medan magnet oleh magnet kekal menghasilkan empat tepat dengan banyak lilitan, di
medan magnet paduan (medan lastik). dalam medan magnet bagi magnet kekal.

The interaction between the magnetic field of the current and It consists of a rectangular copper coil of
the magnetic field of the permanent magnet produces a resultant many turns pivoted in the magnetic field of
magnetic field (catapult field). a permanent magnet.

(b) Medan lastik ini menghasilkan daya gandingan (dalam arah (b) Apabila arus, I, mengalir melalui
yang bertentangan) dan menghasilkan kesan putaran. gegelung , daya putaran akan bertindak
ke atas gegelung.
These catapult fields produce a couple of forces (are in opposite
direction) which produces a turning effect. When the current, I, flows through the coil,
a turning force will be acting on the coil.
(c) Gegelung berputar mengikut arah jam. UNIT 3
The coil rotates in a clockwise direction. (c) Gegelung berputar dan penunjuk
terpesong ke kedudukan baru untuk
Penerangan (d) Apabila gegelung mencapai ke kedudukan menegak, sentuhan menunjukkan magnitud arus, I, yang
Explanation antara berus karbon dan komutator terputus, oleh itu tiada daya mengalir melalui gegelung itu.
putaran memutarkan gegelung itu kerana tiada arus mengalir di
dalamnya. The coil turns and the pointer is deflected
to a new position to indicate the magnitude
When the coil gets to the upright position, the contact between the of the current, I, flowing through the coil.
carbon brushes with the commutators is broken. Therefore there is
no turning force on it because no current flows in the coil. (d) Apabila tiada arus mengalir, spring
pengawal menarik gegelung ke
(e) Tetapi gegelung meneruskan putaran disebabkan kedudukan asal semula dan penunjuk
terpesong semula ke sifar.
inersianya .
When there is no current flow, the control
But, the coil continues to rotate because of its inertia . spring brings the coil back to its original
position and the pointer goes back to zero
(f) Putaran boleh ditingkatkan dengan: deflection.
The turning effect can be increased by:

• meningkatkan magnitud arus yang mengalir.
increasing the magnitude of the current.

• menambahkan bilangan lilitan gegelung.

increasing the number of turns of the coil.

• menambahkan kekuatan medan magnet dengan
memasukkan teras besi lembut.
increasing the strength of the magnetic field by inserting the
iron core.

• menambahkan diameter wayar.

increasing the diameter of the wire.

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Contoh / Example

1 Rajah menunjukkan rod tembaga diletakkan di dalam medan Rod tembaga Magnet kekal
magnet bagi magnet kekal. Brass rod Permanent magnet

Dalam arah manakah rod tembaga itu bergerak apabila suis Bar tembaga
ditutup? Brass bar
The diagram shows a brass rod is placed in the magnetic field of
a permanent magnet.
In which direction does the brass rod move when the switch is
closed?
Penyelesaian / Solution

Dengan menggunakan peraturan tangan kiri Fleming: D
By using Fleming’s left-hand rule: D

3UNIT 2 Rajah menunjukkan arus mengalir dalam wayar yang
tergantung antara dua kutub magnet.

Dalam arah manakah gerakan wayar itu bergerak?
The diagram shows a current flow in a wire hanging between the
poles of a magnet.
In which direction does the wire move?
Penyelesaian / Solution

Dengan menggunakan peraturan tangan kiri Fleming: C
By using Fleming’s left-hand rule: C

3 Rajah menunjukkan arus mengalir di dalam konduktor Konduktor
menembusi permukaan kertas. Conductor

Dalam arah manakah daya bertindak ke atas konduktor? Magnet Magnet
The diagram shows a current flowing in a conductor in the Magnet Magnet
direction into the page.
Which is the direction of the force acting on the conductor?
Penyelesaian / Solution

Dengan menggunakan peraturan tangan kiri Fleming: A
By using Fleming’s left-hand rule: A

4 Rajah menunjukkan wayar membawa arus diletakkan antara
dua kutub magnet.

Dalam arah manakah daya dapat menggerakkan wayar?
The diagram shows a current-carrying wire placed between the
poles of a magnet.
In which direction will the force try to move the wire?
Penyelesaian / Solution

Dengan mengguna peraturan tangan kiri Fleming: A
By using Fleming’s left-hand rule: A

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MODUL • Fizik TINGKATAN 5

Tip Menjawab Soalan SPM

CARA YANG MENARIK UNTUK MENGINGAT BAGAIMANA MELUKIS PASANGAN DAYA LASTIK DALAM
MOTOR ELEKTRIK
AN INTERESTING WAY TO REMEMBER HOW TO DRAW THE COUPLE OF CATAPULT FORCES IN AN
ELECTRIC MOTOR

N
S

Motor arus terus (a.t.)
A direct current (d.c.) motor

Klon Soalan Peperiksaan / Clone examination question : UNIT 3
Terangkan bagaimana sebuah motor arus terus boleh berputar.
Explain how a direct currrent motor is able to rotate.

Penyelesaian / Solution :

Anda boleh jawab soalan ini dengan melukis siri dua gambar rajah, seperti yang ditunjukkkan. Rajah (a) menunjukkan
superposisi dua medan magnet yang berlainan. Rajah (b) menunjukkan hasil saling tindakan antara dua medan magnet ini.
One of the ways to answer this question is two draw a series of two diagrams, as follows. Diagram (a) shows the superposition of two
different magnetic fields. Diagram (b) shows the result of the interaction between these two magnetic fields.

Daya lastik, F
Catapult force, F

NS
NS

Rajah (a) Daya lastik, F
Diagram (a) Catapult force, F

Rajah (b)
Diagram (b)

Untuk mengingat cara melukis medan lastik dalam Rajah (b),
To remember how to draw the catapult field in Diagram (b),

1. Andaikan anda ingin memandu kereta dari titik N ke titik S.
Imagine that you are driving a car from point N to point S.
2. Apabila anda sampai ke bulatan pekeliling pertama, ikutilah arah aliran trafik itu.
When you reach the first roundabout, just follow the direction of the traffic flow of the first roundabout.
3. Apabila anda sampai ke bulatan pekeliling yang kedua itu, ikutilah arah aliran trafik itu juga. Anda akan sampai ke

titik S.
Then, when you reach the second roundabout, follow the direction of traffic flow of the second roundabout. You will then arrive

at point S.
4. Akhirnya, anda mesti menggambarkisahkan 'medan lastik' itu diregangkan seperti dalam sebuah 'katapult' atau lastik.
Finally you need to think of the 'catapult field' as stretched rubber bands in a catapult.
5. Ini akan memberi arah bagi pasangan daya lastik, F, yang ditunjukkan itu.
This will give the directions of the couple of catapult forces, F, as shown.

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MODUL • Fizik TINGKATAN 5

Latihan / Exercise

1 Rajah menunjukkan konduktor membawa arus di dalam medan magnet antara dua Penyelesaian / Solution

magnet kekal. Dalam arah manakah konduktor itu akan bergerak? Jawapan D / Answer D

The diagram shows a current-carrying conductor in a magnetic field between two

permanent magnets. In which direction will the conductor be moved? Penerangan / Explanation

B Dengan menggunakan Peraturan
tangan-kiri Fleming, gerakan
SA CN konduktor adalah ke arah D.
By Fleming’s left-hand rule, motion is
towards D.

D

2 Antara rajah berikut, yang manakah menunjukkan daya yang bertindak ke atas kedua- Penyelesaian / Solution

dua konduktor membawa arus? Jawapan D / Answer D

Which of the following diagrams shows the forces that act on the two parallel current-

carrying conductors correctly? Penerangan / Explanation

A V M C VM Arus dalam kedua-dua wayar adalah

II II sama arah. Oleh itu, terdapat daya
tarikan. VW akan menarik MN.

3UNIT FF FF FF The currents in both wires are in the
same direction. Hence, there is a force
WN WN of attraction. VW will attract MN.

B V M DV M

II II
FF
FF F
WN
WN

3 Rajah menunjukkan litar elektrik yang terdiri daripada sesiri sel kering, reostat dan Penyelesaian / Solution

gegelung wayar. Jawapan A / Answer A

The diagram shows an electrical circuit consisting of a series of dry cells, a rheostat and

a coil of wire. Penerangan / Explanation

Sel kering Reostat Kekuatan medan magnet boleh
Dry cells Rheostat ditingkatkan dengan memasukkan

teras besi ke dalam gegelung. Teras

besi ini dimagnetkan apabila arus

mengalir dalam gegelung itu.

The strength of the magnetic field

Gegelung can be increased by inserting an iron
Coil core into the coil. Iron core is being
magnetized when there is a current

Medan magnet didapati wujud di sekitar gegelung. Antara berikut, yang manakah flowing through the coil.

boleh meningkatkan kekuatan medan magnet?

A magnetic field is found to exist in the vicinity of the coil. Which of the following can

increase the strength of the magnetic field?

A Memasukkan teras besi lembut ke dalam gegelung

Insert an iron core into the coil

B Meningkatkan rintangan pada perintang

Increase the resistance of the resistor

C Menyambungkan sel kering secara selari

Connect the dry cells in parallel

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MODUL • Fizik TINGKATAN 5

4 Arus di dalam gegelung motor arus terus perlu diterbalikkan setiap setengah putaran Penyelesaian / Solution

supaya Jawapan A / Answer A

The current in the coil of a direct current motor needs to be reversed every half rotation

so that Penerangan / Explanation

A mengekalkan putaran dalam satu arah

maintain the rotation in one direction Komutator dalam motor arus terus
B menjana arus ulang-alik menyongsangkan arah arus yang
generate an alternating current mengalir dalam gegelung dan
C mengekalkan kelajuan putaran mengekalkan putaran dalam satu arah.
maintain a constant speed of rotation The commutator in a d.c. motor
D mengekalkan kekutuban magnet reverses the direction of current flow in

maintain the polarities of the magnets the coil to maintain the rotation in one

direction.

5 Gegelung wayar segi empat tepat diletakkan antara dua magnet kekal seperti yang Penyelesaian / Solution

ditunjukkan dalam rajah di bawah. Jawapan C / Answer C

A rectangular coil of wire is placed between two permanent magnets as shown in the

diagram below. Penerangan / Explanation

NS Dengan menggunakan Peraturan UNIT 3
tangan-kiri Fleming, gegelung akan
berputar dalam arah lawan jam.
By Fleming’s left-hand rule, the
coil will rotate in an anticlockwise
direction.

PQ

Apabila arus mantap, I mengalir melalui gegelung pada komutator P dan Q, apakah
kesan yang didapati pada gegelung itu?
When a steady current, I, flows through the coil by way of commutators P and Q, what is
the possible effect on the coil?
A Daya bermagnitud yang sama bertindak ke atas kedua-dua sisi gegelung dan
menjadikan gegelung berada dalam kedudukan mendatar.
Forces of equal magnitude act on the two sides of the coil and keep the coil in the
horizontal position.
B Gegelung akan berputar mengikut arah jam.
The coil will rotate in a clockwise direction.
C Gegelung akan berputar mengikut arah lawan jam.
The coil will rotate in an anticlockwise direction.
D Gegelung akan berputar dan kemudian berhenti dalam kedudukan menegak.
The coil will rotate and then stop in the vertical position.

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UNIT 3 MODUL • Fizik TINGKATAN 5

© Nilam Publication Sdn. Bhd. Aruhan Elektromagnet
3.3 Electromagnetic Induction

Terminologi / Terminology Penerangan / Explanation

Aruhan elektromagnet Penghasilan arus elektrik teraruh dalam suatu konduktor yang berada di medan magnet yang berubah-ubah.
Electromagnetic induction The production of an induced electric current in a conductor which is in a changing magnetic field.

Arus aruhan Terhasil apabila terdapat gerakan relatif antara konduktor atau solenoid dengan medan magnet.
Induced current Is produced when there is a relative motion between conductor or solenoid and the magnetic field.

Daya gerak elektrik teraruh (d.g.e. teraruh) Ialah d.g.e. yang terhasil antara hujung konduktor bergerak atau solenoid dengan magnet kekal
Induced electromotive force (induced e.m.f.) Is the e.m.f. produced between the ends of the moving conductor or solenoid and the permanent magnet

Hukum Faraday tentang aruhan Menyatakan bahawa magnitud d.g.e. teraruh berkadar langsung dengan kadar perubahan fluks magnet atau kadar
elektromagnet
Faraday’s Law of electromagnetic induction pemotongan fluks magnet. / The magnitude of the induced electromotive force (e.m.f.) is directly proportional to the rate of change
of magnetic flux or the rate of cutting the magnetic flux.
Hukum Lenz
Lenz’s Law Menyatakan bahawa arus aruhan sentiasa mengalir pada arah yang menentang perubahan fluks magnet yang

100 menghasilkan arus aruhan ini. / States that an induced current always flows in such a direction so as to oppose the
change of magnetic flux producing this induced current.

Aruhan Elektromagnet / Electromagnetic Induction

Disebabkan oleh Syarat-syarat
Because of Requirement

(a) Pemotongan fluks (b) Perubahan fluks oleh Untuk menghasilkan arus teraruh: Nota/Note:
magnet gegelung In order to produce an induced current: Untuk menentukan arah arus
teraruh yang mengalir dalam
Cutting of magnetic Change of flux lingkage (a) gerakan konduktor mesti memotong garis medan konduktor, peraturan tangan-
flux by the coil magnet (fluks magnet) kanan Fleming digunakan
(Peraturan Dinamo):
Galvanometer Solenoid a moving conductor must cut across the magnetic field To determine the direction
Galvanometer Solenoid lines (magnetic flux). of a current induced in
a conductor, Fleming's
Wayar (b) mesti ada perubahan garis medan magnet oleh right-hand rule is used
Wire gegelung. (Dynamo Rule):

Bar magnet there must be a change of magnetic field lines linkage
Magnet bar by a coil.

Galvanometer
Galvanometer

Magnitud d.g.e. aruhan dan arah arus teraruh boleh ditentukan menggunakan Daya gerakan, M
hukum Lenz dan hukum Faraday. Motion, M

Medan magnet, B
Magnetic field, B

S

The magnitude of the induced e.m.f. and direction of the induced current can be determined

Lenz's law N

by application of and Faraday's law.

Arus aruhan, I
Induced current, I

Hukum Aruhan Elektromagnet
Laws of Electromagnetic Induction

Hukum Lenz / Lenz’s Law Hukum Faraday / Faraday’s Law
Untuk menentukan arah arus teraruh / To determine the direction of the induced current
Untuk menentukan magnitud arus teraruh
PQ P Q To determine the magnitude of the induced
current

Berdasarkan Hukum Faraday:
Based on Faraday’s Law:

Arus aruhan atau d.g.e aruhan boleh
ditingkatkan jika:
The induced current or induced e.m.f can be
increased if:

(a) bilangan lilitan solenoid
bertambah .

the number of turns of the solenoid
increases .
MODUL • Fizik TINGKATAN 5
101 © Nilam Publication Sdn. Bhd.
(a) Apabila magnet digerakkan mendekati solenoid, arus diaruhkan di dalam solenoid, maka hujung P mesti diaruhkan
untuk menjadi kutub utara maka daya tolakan wujud antara solenoid dan magnet. [Perhatian: Mengikut Hukum Lenz, P
menjadi kutub utara untuk menentang gerakan magnet masuk ke dalam solenoid]

(b) Apabila magnet digerakkan menjauhi solenoid, hujung P diaruhkan untuk menjadi kutub selatan , maka
daya tarikan wujud antara solenoid dan magnet.

(c) Oleh itu, apabila magnet bergerak mendekati atau menjauhi solenoid, kerja dilakukan untuk mengatasi daya yang
bertentangan. Kerja yang dilakukan ditukarkan kepada tenaga elektrik yang menghasilkan arus aruhan .

(a) When the magnet is moved towards the solenoid, current is induced in the solenoid, hence the end P must be induced to become (b) kekuatan magnet bertambah .
the north pole so that a force of repulsion exists between the solenoid and the magnet. the strength of the magnet increases

[Note: According to Lenz’ Law, P becomes the north pole so as to oppose the motion of the magnet from entering the solenoid]

south .

(b) When the magnet is moved away from the solenoid, the end P is induced to become the pole so that a (c) laju gerakan relatif antara magnet dan
force of attraction exists between the solenoid and the magnet. solenoid bertambah.

(c) Therefore when the magnet is move towards or away from a solenoid, work must be done to overcome the opposing force. The the speed of relative motion between the
work done is converted into electrical energy which creates the induced current . magnet and solenoid increases.

3UNIT

UNIT 3 MODUL • Fizik TINGKATAN 5

HUKUM-HUKUM ARUHAN ELEKTROMAGNET (Klasifikasi) / LAWS OF ELECTROMAGNETIC INDUCTION (Classifying)

Hukum Aruhan Elektromagnet
Laws of Electromagnetic Induction
Video

Hukum Lenz
Lenz's Law

https://goo.gl/2oEQSM

© Nilam Publication Sdn. Bhd.
Hukum Lenz Hukum Faraday
Lenz’s Law Faraday’s Law

Menyatakan bahawa arus aruhan terhasil sentiasa mengalir pada arah yang Menyatakan bahawa magnitud d.g.e teraruh berkadar langsung dengan kadar
menentang perubahan fluks magnet yang menghasilkannya perubahan fluks magnet atau kadar pemotongan fluks magnet
State that an induced current always flows in such a direction so as to oppose the States that the magnitude of the induced e.m.f. is directly proportianal to the rate of
change of magnetic flux producing this induced current change of magnetic flux or the rate of cutting of the magnetic flux
(a) Arus teraruh menghasilkan fluks magnet yang menentang gerakan
102 GMGMeorteoiarotkianoaknnoafnomafmaamgamanggaenngteenttet MGMGeorteoiarotkianoaknnoafnomafmaamgamanggaenngteenttet
magnet masuk ke dalam solenoid itu. Kutub selatan (S) dihasilkan pada
hujung solenoid menentang kutub selatan (S) magnet yang bergerak masuk
ke solenoid.
Induced current produces a magnetic flux that opposes the motion of the
magnet entering the solenoid. South pole (S) is produced at the end of the
solenoid against the south pole (S) of the magnet to move into solenoid.

Magnet dimasukkan GMGMeorteoiarotkianoaknnoafnomafmaamgamanggaenngteenttet MGMGeorteoiarotkianoaknnoafnomafmaamgamanggaenngteenttet
Magnet is put in

(b) Arus teraruh mengalir pada arah (seperti di bawah) supaya menghasilkan Arus aruhan atau d.g.e aruhan boleh ditingkatkan melalui:
fulonwtuskinmtehneadriirkecmtiaognn(eaMMtsaaysggahnnnoeegwtt iddnsiimpbkueeatlslouuinwkakr)katnaonp.roduce The induced current or induced e.m.f can be increased by:
kutub utara (U) north pole (a) meningkatkan kelajuan gerakan relatif antara magnet dan solenoid
Induced current increasing the speed of relative motion between the magnet and solenoid
(b) meningkatkan kekuatan medan magnet
(N) to attract the magnet from moving away from the solenoid. increasing the strength of the magnet field
Magnet dikeluarkan (c) menambahkan bilangan lilitan pada solenoid
increasing the number of turns of solenoid
Magnet is taken out

Magnet dikeluarkan
Magnet is taken out

MODUL • Fizik TINGKATAN 5

Gerakan relatif untuk menghasilkan arus teraruh
Relative motion to produce induce currents

Mekanisme penghasilan arus teraruh atau d.g.e teraruh:
Mechanism of the production of induced current or induced e.m.f.:

Apabila gerakan relatif antara konduktor dan magnet dilakukan, konduktor akan memotong garis medan magnet dan mengubah
fluks magnet. / Whenever there is a relative motion between a conductor and a magnet, the conductor cuts across the magnetic lines of
force and changes the magnetic flux.

Rajah Gerakan relatif Rajah menunjukkan arus
Diagram Relative motion teraruh dihasilkan

Solenoid Arus aruhan dihasilkan apabila: Diagram shows the induced current occurs
Solenoid Induced current is produced when:

Magnet bar (a) Gerakan magnet ke dalam Galvanometer akan terpesong.
Bar magnet The galvanometer will show a deflection.
solenoid yang pegun , atau
Galvanometer berpusat sifar gerakan magnet melintasi wayar yang
Zero centred galvanometer pegun. / Moving the magnet into a

stationary solenoid or moving
the magnet over a stationary wire.

Galvanometer (b) Gerakan wayar / solenoid over UNIT 3
berpusat sifar melintasi magnet pegun.
Zero centred Wayar kuprum
galvanometer Copper wire Moving the wire / solenoid
a stationary magnet.
Magnet Dening
magnadur besi (c) Gerakan magnet dan wayar / solenoid
Magnadur bentuk-U dalam arah bertentangan.
magnet Iron yoke
Moving magnet and wire / solenoid in
the opposite directions.

(d) Gerakan magnet dan wayar / solenoid
dalam arah yang sama tetapi pada laju

berbeza .

Moving the magnet and wire /

solenoid in the same direction but at

different speeds.

Arus teraruh dihasilkan apabila: Galvanometer akan terpesong.
Induced current is produced when: The galvanometer will show a deflection.

P Q (a) Menutup dan membuka suis S. PQ
S Closing and opening switch S.

R (b) Melaraskan reostat R . S
Adjusting rheostat R .

(c) Gerakan gegelung P mendekati atau R
menjauhi gegelung Q.

Moving the coil P nearer to or further
from the coil Q.

(d) Menggantikan bateri dengan bekalan
kuasa arus ulang-alik dan suis S
ditutup.

Replacing the battery with a.c. power
supply and close the switch.

103 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Magnet bar Galvanometer Arus teraruh dihasilkan apabila: Galvanometer akan terpesong.
Bar magnet berpusat sifar Induced current is produced when: The galvanometer will show a deflection.
Zero centred
galvanometer mengayunkan
dalam medan magnet.
Ladung bandul di
Bob

oscillating the pendulum bob in
a magnetic field.

Wayar kuprum

Magnet bar Copper wire

Bar magnet

Konduktor

Conductor

Eksperimen Eksperimen untuk menentukan magnitud arus teraruh
Experiment An experiment to determine the magnitude of an induced current

3UNIT Inferens Magnitud arus teraruh bergantung kepada laju gerakan relatif antara magnet dan konduktor.
Inference The magnitude of an induced current depends on the speed of the relative motion between the conductor and
magnet.
Hipotesis
Hypothesis Laju gerakan relatif antara magnet dan konduktor bertambah (diukur melalui ketinggian magnet di atas
solenoid), maka magnitud arus teraruh bertambah.
As the speed of the relative motion between the conductor and magnet increases (indicated by height of the magnet
above the solenoid), the magnitude of the induced current also increases.

Tujuan Mengkaji hubungan antara laju gerakan relatif antara magnet dan konduktor dengan magnitud arus teraruh.
Aim To investigate the relationship between the speed of the relative motion between the conductor and magnet and the
magnitude of an induced current.
Pemboleh ubah
Variables Pemboleh ubah dimanipulasikan: / Manipulated variable:
Laju gerakan relatif antara konduktor dan magnet. Laju ini diwakili oleh ketinggian magnet di atas solenoid, H,

sebelum magnet dilepaskan. / The speed of the relative motion between the conductor and magnet. This speed is

represented by the height, H, of the magnet above the solenoid, before it is released.

Pemboleh ubah bergerak balas: / Responding variable:
Magnitud arus teraruh / The magnitude of the induced current

Pemboleh ubah dimalarkan: / Constant variable:
Bilangan lilitan solenoid dan kekuatan magnet / Number of turns of solenoid and the strength of the magnet

Senarai radas dan Galvanometer berpusat sifar yang sensitif, solenoid, magnet bar dan pembaris.
bahan Sensitive zero-centre galvanometer, solenoid, bar magnet and ruler.
List of apparatus
and materials

© Nilam Publication Sdn. Bhd. 104

MODUL • Fizik TINGKATAN 5

Susunan radas Pembaris Magnet bar
Arrangement of the Ruler Bar magnet
apparatus
Solenoid
Solenoid

Paip PVC (atau kadbod)
PVC (or cardboard) pipe

Prosedur 1 Ketinggian magnet di atas solenoid diukur dengan pembaris, H = 2.0 cm.
Procedure The height of the magnet above the solenoid is measured by a ruler, H = 2.0 cm.

2 Magnet dijatuhkan ke dalam solenoid dan bacaan galvanometer dicatatkan = I.
The magnet is dropped into the solenoid and the reading of the galvanometer is recorded = I.

3 Eksperimen diulangi dengan ketinggian magnet di atas solenoid yang berbeza,
H = 4.0 cm, 6.0 cm, 8.0 cm dan 10.0 cm.
The experiment is repeated with different heights of the magnet above the solenoid, H = 4.0 cm, 6.0 cm,
8.0 cm and 10.0 cm.

Penjadualan data Ketinggian magnet / Height of magnet, H / cm 2.0 4.0 6.0 8.0 10.0 UNIT 3
Tabulation of the Arus teraruh / Induced current, I / μA
data

Arus teraruh / Induced current
I / μA

Analisis data
Analysis of the data

Ketinggian magnet

0 Height of magnet
H / cm

Aplikasi Aruhan Elektromagnet
Applications of Electromagnetic Induction

Penjana Arus Terus / D.C. Generator Penjana Arus Ulang-alik / A.C. Generator

Magnet kekal Putaran Putaran Magnet kekal
Rotation Permanent magnet
Permanent magnet Rotation
CD
CD

N S N S
B A B A

Gegelung satah/angker Komutator Berus karbon Gegelung satah/angker
Coil Carbon brush
}Commutator Coil } Litar luar
Berus karbon Q P Arus Litar luar Galvanometer Gelang External
Carbon brush Current External Galvanometer gelincir circuit
circuit Slip rings

Galvanometer
Galvanometer

AA BB A A 10A5 A BB © NilamA PubAlication Sdn. Bhd.
Q PQ QP PQA QP A PQ QP
PQB QP B PQ P B BA AA AB B

MODUL • Fizik TINGKATAN 5

AA AA BB BB AA AA AA AA BB BB AA AA
QQ PP QQ PP AA QQQQ PP AA QQ PP BB QQQQ PP BB QQ PP
BB AABB AA BBAA BB
BB BB AA AA

BB BB AA AA BB BB BB BB AA AA BB BB
(a) (b) (c) (d) (e) (a) (b) (c) (d) (e)
d.g.e. = 0 d.g.e. = d.g.e. = 0 d.g.e. = d.g.e. = 0 d.g.e. = 0 d.g.e. = d.g.e. = 0 d.g.e. = d.g.e. = 0
e.m.f. = 0 maksimum e.m.f. = 0 maksimum e.m.f. = 0 e.m.f. = 0 maksimum e.m.f. = 0 maksimum e.m.f. = 0
e.m.f. = e.m.f. = e.m.f. = e.m.f. =
maximum maximum maximum maximum

d.g.e teraruh d.g.e teraruh
induced e.m.f. induced e.m.f.

Bilangan Bilangan

putaran putaran

0 Number of 0 Number of

rotations rotations

3UNIT (a) Apabila angker/gegelung satah dalam keadaan menegak, (a) Bermula dengan gegelung satah/angker dalam keadaan
sisi BC dan AD bergerak selari dengan garis medan magnet. menegak, sisi BC dan AD bergerak dalam keadaan selari
Maka, tiada pemotongan garis medan magnet. Maka, tiada dengan garis medan magnet. Maka, tiada pemotongan garis
medan magnet. Maka, tiada arus aruhan dihasilkan.
arus aruhan dihasilkan.
When the plane of the coil is in a vertical position, the sides Starting with the plane of the coil in the vertical position, the
sides BC and AD move parallel with the magnetic field lines.
BC and AD move parallel with the magnetic field lines. There is no cutting of magnetic lines of force. Therefore, no
There is no cutting of magnetic lines of force. Therefore, no induced current is produced.

induced current is produced.

(b) Dalam keadaan mendatar, BC bergerak ke atas dan AD (b) Dalam keadaan mendatar, BC bergerak ke atas dan
bergerak ke bawah. Sisi BC dan AD memotong garis AD bergerak ke bawah. Sisi BC dan AD memotong
medan magnet pada sudut tepat. Oleh itu, arus teraruh yang
garis medan magnet pada sudut tegak. Oleh itu,

maksimum arus teraruh dan d.g.e. teraruh yang maksimum dihasilkan.

dihasilkan serta d.g.e. maksimum In the horizontal position, BC moves upwards and AD moves

diaruhkan. / In the horizontal position, BC moves upwards and downwards. The sides BC and AD cut the magnetic field lines
at right angles. Hence, the induced current produced is
AD moves downwards. The sides BC and AD cut the magnetic maximum and the induced e.m.f. is maximum.

field lines at right angles. Hence, the induced current produced

is maximum and the induced e.m.f. is maximum. (c) Selepas keadaan ini, arus teraruh (d.g.e. teraruh) berkurangan
sehingga ke sifar, apabila angker/gegelung satah dalam
(c) Selepas keadaan ini, arus teraruh (d.g.e. teraruh) berkurangan
sehingga ke sifar apabila angker/gegelung satah dalam keadaan menegak semula kerana tiada
keadaan menegak semula kerana tiada pemotongan garis
medan magnet. pemotongan garis medan magnet.

After this position, the current starts to decrease until it is zero After this position, the current starts to decrease until it is zero
when the plane of the coil is in a vertical position because the
magnetic field lines are not cut. when the plane of the coil is in a vertical position

because the magnetic field lines are not cut.

(d) Arah arus di dalam litar luar tidak berubah. (d) Proses ini diulang.
The direction of the current in the external circuit does not The process is repeated.

change.

(e) Proses ini diulang. (e) Arah arus di dalam litar luar berubah-ubah setiap kali
The process is repeated. gegelung/angker melepasi keadaan menegak.

terus The direction of the current in the external circuit changes each
time the coil passes the vertical position.

(f) Arus dalam litar luar ialah arus (iaitu, ulang-alik

arus yang mengalir dalam satu arah). (f) Arus dalam litar luar ialah arus .

The current in the external circuit is a direct The current in the external circuit is an alternating
current.
current (that is, the current flows in one direction).

© Nilam Publication Sdn. Bhd. 106

MODUL • Fizik TINGKATAN 5

Teknik Menjawab [Format Kertas 2 : Perbandingan]
Answering Technique [Paper 2 Format : Comparison]

Rajah (a) menunjukkan seorang budak perempuan sedang mengayuh basikal di jalan rata pada waktu malam. Rajah (b) menunjukkan
basikal tersebut dikayuh mendaki bukit yang curam pada waktu malam. Rajah (c) menunjukkan reka bentuk dinamo basikal tersebut.
Diagram (a) shows a girl cycling on flat roads at night. Diagram (b) shows the bike cycled climbing a steep uphill road. Diagram (c) shows
design of the bicycle’s dynamo.

Malap Magnet kekal Pencengkam roda
Dim Permanent Wheel grip
magnet
Teras besi
Cerah Iron core
Bright Gegelung dawai
Wire coil

Punca bertebat
Insulated source

Jalan rata Jalan mendaki bukit Dinamo (c)
Flat road Climb uphill road Dynamo (c)

(a) (b)

(a) Lengkapkan jadual di bawah dengan membandingkan aspek-aspek yang dinyatakan dalam jadual:
Complete the table below by comparing the aspects mentioned:

Aspek / Aspect Rajah (a) / Diagram (a) Rajah (b) / Diagram (b) UNIT 3

Laju kayuhan basikal Lebih laju Kurang laju
The cycling speed of the bike Higher speed Lower speed

Kadar pemotongan fluks magnet oleh gegelung dawai dinamo Lebih besar Lebih kecil
The cutting rate of magnetic flux by the coil wire of dynamo Larger Smaller

Keadaan nyalaan mentol Lebih cerah Kurang cerah
Lighting condition of bulb Brighter Dimmer

Arus elektrik yang terhasil Lebih besar Lebih kecil
Current produced Larger Smaller

(b) Hubung kaitkan: / Relate:
(i) laju kayuhan basikal dan keadaan nyalaan mentol. / the cycling speed of bike and the lighting condition of bulb.
Semakin bertambah laju kayuhan basikal, semakin cerah nyalaan mentol.
As the cycling speed of bike increases, the bulb lights up brighter.

(ii) kadar pemotongan fluks magnet oleh gegelung dawai dinamo dan arus elektrik yang terhasil.
the cutting rate of magnetic flux by the coil wire of dynamo and current produced.
Apabila kadar pemotongan fluks magnet oleh gegelung dawai dinamo semakin bertambah, arus elektrik yang
terhasil semakin bertambah.
As the cutting rate of magnetic flux by the coil wire of dynamo increases, the current produced increases.

(c) Berdasarkan jawapan-jawapan anda di (b)(i) dan (b)(ii), deduksikan
Based on your answers in (b)(i) and (b)(ii), deduce
(i) konsep fizik / physics concept: Aruhan elektromagnet / Electromagnetic induction
(ii) hukum fizik / laws of physics: Hukum Lenz / Lenz’s law

107 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Teknik Menjawab [Format Kertas 2 : Kefahaman / Esei Pendek]
Answering Technique [Paper 2 Format : Comprehension / Short Essay]

Dinamo basikal / Bicycle’s dynamo

Terangkan bagaimana dinamo menyalakan lampu basikal. • Magnet kekal diputarkan.
Explain how the dynamo lights up the bike’s bulb.

[4 markah / marks] The permanent magnet is rotated.

Magnet kekal Pencengkam roda • Fluks magnet dipotong oleh gegelung dawai secara gerakan relatif.
Permanent Wheel grip The magnetic flux is cut by the coil wire through the relative motion.
magnet
Teras besi • Arus aruhan terhasil melalui aruhan elektromagnet.
Kotak dinamo Iron core The induced current produced through the electromagnetic induction.
Dynamo box Gegelung dawai
Wire coil • Tenaga kinetik → Tenaga elektrik → Tenaga cahaya

Punca bertebat Kinetic energy → Electric energy → Light energy
Insulated source

3UNIT Teknik Menjawab [Format Kertas 2 : Bahagian B]
Answering Technique [Paper 2 Format : Part B]

Cadang dan terangkan pengubahsuaian untuk menjadikan dinamo berfungsi secara lebih berkesan.
Suggest and explain modifications to make the dynamo work more efficiently.

Cadangan / Suggestion Sebab / Reason

Kekuatan magnet kekal: Menghasilkan arus yang lebih besar [M2]
Strength of permanent magnet: [M1] Produce larger induced current

Lebih kuat / Stronger

Bahan teras: Mudah dimagnet dan mudah dinyah-magnetkan [M4]
Material of core: [M3] Easier to be magnetised and easier to be demagnetised

Besi lembut / Soft iron

Bilangan lilitan gegelung dawai: Menambahkan kadar pemotongan fluks magnet [M6]
The number of turns of coil wire: [M5] To increase the cutting rate of magnetic flux

Lebih banyak / More

Luas keratan rentas / diameter dawai untuk membuat gegelung: Rintangan lebih kecil [M8]
Cross sectional area / diameter of wire of coil: [M7] Smaller resistance

Lebih besar / Larger

Bahan yang sesuai untuk gegelung dawai: Rintangan lebih kecil [M10]
Suitable material of coil wire: [M9] Smaller resistance

Kuprum / Copper

Saiz / diameter pencengkam roda: Menambahkan kadar pemotongan fluks magnet [M12]
Size / diameter of wheel gripper: [M11] To increase the cutting rate of magnetic flux

Lebih kecil / Smaller

© Nilam Publication Sdn. Bhd. 108

MODUL • Fizik TINGKATAN 5

Perbandingan antara Arus Terus dan Arus Ulang-alik
Comparison between Direct Current and an Alternating Current

Arus terus / Direct current Arus ulang-alik / Alternating current

Maksud: / Meaning: satu arah yang tetap sahaja. Maksud: / Meaning:
Arus yang mengalir dalam one fixed direction only. Arus yang mengalir pergi dan balik dalam arah berlawanan
The current flowing in secara berkala.
The current flowing to and from in opposite directions periodically.

Menghasilkan medan magnet yang tetap pada konduktor elektrik. Menghasilkan medan magnet yang berubah-ubah pada konduktor

Generates fixed magnetic field on the electrical conductor. elektrik. / Generates varying magnetic field on the electrical conductor.

Boleh mengalir melalui perintang tetapi tidak boleh mengalir Boleh mengalir melalui perintang dan kapasitor.
melalui kapasitor. Can flow through the resistor and capacitor.
Can flow through the resistor but cannot flow through the capacitor.

Sumber: bateri atau sel kering / Source: battery or dry cell Sumber: Bekalan kuasa TNB (Dijana dengan frekuensi 50 Hz)
Simbol / Symbol : Source: TNB power supply (Generated with a frequency of 50 Hz )

Simbol / Symbol :

Sumber a.t. / d.c. source Sumber a.u.
a.c. source

I (A) I (A) I (A) I (A) UNIT 3
t (s)
t (s)

t (s) t (s)

Arus dari bateri Arus dari penjana a.t. Magnitud arus adalah tetap, Magnitud dan arah arus berubah,
Current from battery Current from d.c. generator arah berlawanan arus dari penjana a.u

The magnitude of current is Magnitude and direction of
fixed, opposite direction current are changing, current from

a.c. generator

Latihan / Exercise

1 Rajah menunjukkan arus ulang-alik di mana magnitud berubah dengan masa.
The diagram shows an alternating current with a magnitude that changes with time.

I/A (a) Apakah arus puncak?
5.0 What is the peak current?
(b) Apakah tempoh arus ulang-alik?
0 0.02 0.04 0.06 0.08 0.10 t/s What is the period of the alternating current?
(c) Apakah frekuensi arus ulang-alik?
What is the frequency of the alternating current?

–5.0

Penyelesaian / Solution
(a) 5 A (daripada graf / from the graph)

(b) 0.04 s (daripada graf / from the graph)

(c) f = —­ —1 — = 25 Hz
0.04 s

109 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Transformer
3.4 Transformers

Transformer Alat yang digunakan untuk meningkatkan atau menurunkan beza Teras besi lembut berlapis
Transformers keupayaan bekalan arus ulang-alik berdasarkan prinsip aruhan Laminated soft iron core
elektromagnet. / Electrical device which increases or decreases an
Struktur Gegelung
Structure alternating current based on the principle of electromagnetic induction. Coil

Simbol `` Terdiri daripada dua gegelung wayar yang dililitkan berasingan pada Nota / Note:
Symbol teras besi lembut berlapis. / Consists of two coils of wire wound round • Frekuensi beza keupayaan
separately on a laminated soft-iron core.
Prinsip sekunder, Vs, adalah sama
kerja `` Gegelung yang disambungkan kepada voltan input dinamakan dengan frekuensi beza
Working gegelung primer . / The coil connected to the input voltage is keupayaan primer, Vp.
principle The frequency of the secondary
called the primary coil . voltage, Vs is the same as that of
the primary voltage, Vp.
`` Gegelung yang disambungkan kepada voltan output dinamakan • Magnitud beza keupayaan
sekunder, Vs bergantung kepada
gegelung sekunder . kadar bilangan lilitan gegelung
primer dan sekunder.
The coil connected to the output voltage is called the secondary coil . The magnitude of the secondary
voltage, Vs depends on the ratio
3UNIT 240 V 24 V of the number of turns of the
primary and secondary coils.
Gegelung primer Gegelung sekunder
Primary coil Secondary coil

• Transformer bekerja berdasarkan prinsip aruhan elektromagnet.
A transformer works on the principle of electromagnetic induction.

• Apabila beza keupayaan ulang-alik, Vp, dibekalkan ke gegelung primer,
arus ulang-alik mengalir melalui gegelung.

When an a.c. voltage, Vp , is applied to the primary coil of the transformer,

an alternating current flows through the coil.

• Teras besi lembut dimagnetkan. / The soft-iron core is magnetised.

• Arus ulang-alik mempunyai arah dan magnitud yang berubah. Oleh itu,
terdapat perubahan arah dan magnitud medan magnet.
An alternating current has varying directions and magnitudes.
So there is a change in the direction and magnitude of magnetic field.

• Teras besi lembut membekalkan medan magnet yang berubah-ubah arah
dan magnitud dalam gegelung sekunder. / The soft-iron core provides a
varying magnetic field in the secondary coil.

• Medan magnet yang berubah-ubah juga wujud dalam gegelung
sekunder. / A varying magnetic field also occurs in the secondary coil.

• Medan magnet yang berubah-ubah akan menghasilkan

arus aruhan dan d.g.e ulang-alik teraruh, Vs, dalam

gegelung sekunder. / The varying magnetic field will produce an

induced current and alternating voltage, Vs in the secondary coil.

© Nilam Publication Sdn. Bhd. 110

Ciri-ciri Kuasa / Power MODUL • Fizik TINGKATAN 5
Characteristics
Dalam transformer unggul, tiada tenaga yang hilang semasa proses Nota/Note:
pemindahan beza keupayaan. Mengapakah transformer tidak UNIT 3
In an ideal transformer, there is no energy loss during the process of boleh berfungsi dengan bekalan
transforming the voltage. kuasa arus terus?
Why the transformer does not work
Oleh itu, kuasa output = kuasa input with a d.c. power supply?
Hence, output power = input power
• Jika beza keupayaan arus terus
Is Vs = Ip Vp digunakan pada gegelung
primer, beza keupayan output
Di mana / where, pada gegelung sekunder akan
Is = Arus sekunder / Secondary current menjadi sifar.
Ip = Arus primer / Primary current If d.c. voltage is applied to the
Vs = Beza keupayaan sekunder / Secondary potential difference primary coil of the transformer,
Vp = Beza keupayaan primer / Primary potential difference the output voltage at the
secondary coil will be zero.
Kecekapan / Efficiency
• Ini adalah kerana bekalan
Dalam transformer sebenar, sebahagian tenaga akan hilang akibat dari: kuasa arus terus membekalkan
In real transformers, some energy will be lost due to: arus mantap dalam gegelung
(a) kesan pemanasan dalam gegelung dawai primer di mana ia mempunyai
magnitud tetap dan arah yang
heating effect in the coils tetap.
(b) kesan arus pusar yang teraruh dalam teras besi This is because a d.c. power
supply gives a constant current in
eddy currents which are induced in the iron core primary coil which has constant
(c) memagnetkan dan menyahmagnetkan teras besi magnitude and direction.

magnetisation and demagnetisation of iron core • Oleh itu, medan magnet yang
(d) kebocoran garis medan magnet (fluks magnet) dihasilkan di dalam teras besi
lembut mempunyai magnitud
leakage of magnetic field lines (magnetic flux leakage) dan arah yang tetap.
So the magnetic field produced
Kecekapan = Kuasa output × 100% in the soft iron core has constant
Kuasa Input magnitude and direction.
Kecekapan
Efficiency Output power • Teras besi lembut tidak
Input power membentuk garis medan
Efficiency = × 100% magnet berubah-ubah di dalam
gegelung sekunder.
Ns = Vs The magnet does not create a
Np Vp changing magnetic flux in the
secondary coil.
Di mana / where

Rumus Ns = Bilangan lilitan gegelung sekunder
Formula = Number of turns in the secondary coil

Np = Bilangan lilitan gegelung primer
= Number of turns in the primary coil

Vs = Beza keupayaan sekunder
= Secondary potential difference

Vp = Beza keupayaan primer
= Primary potential difference

111 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

JENIS TRANSFORMER (Klasifikasi)
TYPES OF TRANSFORMERS (Classifying)

Rajah / Diagram Gegelung sekunder Rajah / Diagram
disambung kepada

voltan output
Secondary coil is
connected to output

voltage

3UNIT VS > VP Transformer Formula: Transformer VS < VP
NS > NP Injak Naik —NNPS– = —VVPS– Injak Turun NS < NP

Step-up Gegelung primer Step-down
transformer disambung kepada transformer

voltan input
Primary coil is
connected to input

voltage

Video Dua gegelung wayar
dililit berasingan pada
Transformer
Transformer teras besi lembut
https://goo.gl/ycstGS berlamina / Two coils
of wire wound round
© Nilam Publication Sdn. Bhd. separately on a laminated

soft-iron core

112

MODUL • Fizik TINGKATAN 5

Faktor yang mempengaruhi kecekapan transformer dan cara untuk meningkatkan kecekapannya
Factors that affect the efficiency of a transformer and ways to improve the efficiency

Punca kehilangan tenaga Cara mengatasi Sebab
Cause of energy loss Way to overcome Reason

Rintangan gegelung : Gunakan dawai kuprum tebal • Rintangan lebih rendah.
The resistance of coil : sebagai gegelung. Lower resistance.
• kesan pemanasan / the effect of heating Use thick copper wire as
• menghasilkan haba / heat is produced coil. • Mengurangkan penghasilan
• E = Q = I2Rt
haba .
To reduce the heat produce.

Kesan histerisis / Hysterisis effect Gunakan teras besi lembut. Besi lembut lebih mudah dimagnetkan dan
• Kehilangan tenaga semasa proses Use soft iron core. lebih mudah dinyah-magnetkan.
Soft iron is easy to be magnetised and easy to
pemagnetan dan penyah-magnetan. be demagnetised.
Loss of energy during the process of
magnetisation and demagnetisation.
• Tenaga hilang dalam bentuk haba.
Energy is lost in form of heat.

Kebocoran fluks magnet . (i) Reka bentuk teras : Sambungan fluks magnet lebih baik antara
Design of core: gegelung primer dan gegelung sekunder.
The leakage of magnetic flux . Better linkage of magnetic flux between the
(ii) Melilitkan gegelung sekunder di primary coil and the secondary coil.
• Tenaga elektrik hilang kerana kehilangan atas gegelung primer.

sebahagian fluks magnet yang terhasil di Wind the secondary coil on the top of UNIT 3
the primary coil.
gegelung primer.
(iii) Mengurangkan jarak antara
Electrical energy is lost due to loss a part gegelung sekunder dan gegelung
primer.
of the magnetic flux in the primary coil.
Reduce the distance between the
• Menyebabkan d.g.e teraruh di gegelung primary coil and the secondary coil.

sekunder menjadi lebih kecil.

Causing induced e.m.f in the secondary

coil becomes smaller.

Arus pusar dalam teras. Teras berlamina is used. Menghasilkan haba arus
Eddy currents in the core. pusar. the eddy currents.
• Pemutaran elektron dalam teras digunakan. To heat
Laminated core
disebabkan medan magnet yang berubah-
ubah. / Rotation of electrons in the core as
magnetic field changing.

Latihan / Exercise

1 Bilangan lilitan dalam gegelung primer dan gegelung sekunder pada transfomer masing-masing ialah 50 dan 250. Apakah beza
keupayaan output apabila transformer menggunakan bekalan kuasa 12 V?
The number of turns in the primary and secondary coil of a transformer are 50 and 250 respectively. What is the output voltage when
the transformer is using a voltage of 12 V?
Penyelesaian / Solution

Diberi / Given Ns= 250 lilitan / turns, Np= 50 lilitan / turns, Vp = 12 V

Ns = Vs
Np Vp

Vs = Ns Vp
Np

= 250 lilitan / turns × 12 V = 60 V
50 lilitan / turns

113 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

2 Rajah menunjukkan 12 V, 36 W mentol menyala dengan 4 Rajah menunjukkan 12 V, 48 W mentol menyala dengan
kecerahan normal apabila disambungkan kepada bekalan kecerahan normal apabila disambungkan kepada bekalan
kuasa 240 V melalui transformer. Bilangan lilitan gegelung kuasa 240 V melalui transformer.
primer ialah 500. The diagram shows a 12 V, 48 W bulb light up with
The diagram shows a 12 V, 36 W bulb light up with normal normal brightness when it is connected to a 240 V mains
brightness when it is connected to a 240 V mains supply supply through a transformer.
through a transformer. The number of turns of the primary
coil is 500. 0.3 A

240 V 12 V, 36 W 240 V 12 V, 48 W

Berapakah bilangan lilitan gegelung sekunder? Ns = 200
What is the number of turns of the secondary coil?
Penyelesaian / Solution Hitungkan / Calculate
(a) bilangan lilitan gegelung primer.
Diberi / Given Vs= 12 V, Vp= 240 V, Np = the number of turns of the primary coil.
500 lilitan / turns (b) arus dalam gegelung sekunder.
the current in the secondary coil.
Ns = Vs (c) kecekapan transformer.
Np Vp the efficiency of the transformer.
Penyelesaian / Solution
500 Ns / turns = 12 V
lilitan 240 V
Diberi / Given Vp = 240 V, Ns = 200 lilitan / turns,
Ns = 12 V × 500 lilitan / turns

3UNIT 240 V Vs = 12 V, Ip = 0.3 A

= 25 lilitan / turns (a) Ns = Vs
Np Vp

3 Transformer injak-turun disambungkan ke bekalan kuasa 200 lilitan / turns = 12 V
240 V dan memberikan kuasa 90 W kepada komputer Np 240 V
riba, 30 V.
Np = 240 V × 200 lilitan / turns
KBAT [Andaikan transformer adalah unggul.] 12 V
A step-down transformer connected to 240 V mains power
supply delivers 90 W of power at 30 V to a notebook computer. Np = 4 000 lilitan / turns
[Assume that the transformer is ideal.]
(b) Vs = 12 V, Ps = 48 W
Hitungkan / Calculate
(a) arus dalam gegelung sekunder. \ Is = Ps = 48 W = 4.0 A
the current in the secondary coil. Vs 12 V
(b) arus dalam gegelung primer.
the current in the primary coil. (c) Kuasa output / Output power = 48 W
Penyelesaian / Solution
Kecekapan / Efficiency = Poutput × 100%
Pinput
Diberi / Given Vp = 240 V, Poutput = 90 W, Vs = 30 V
48 W
(a) Poutput = Is Vs (b) Ip Vp = Is Vs = Ip Vp × 100%

90 W = Is × 30 V Ip × 240 V = 3 A × 30 V = 48 W × 100%
90 W 0.3 A × 240 V
Is = 90 W Ip = 240 V
30 V = 66.67%

Is = 3 A = 0.375 A

atau

Kuasa input = Kuasa output
Input power = Output power

Jadi, / Therefore,

Ip Vp = 90 W
90 W

\ Ip = 240 V

Ip = 0.375 A

© Nilam Publication Sdn. Bhd. 114

MODUL • Fizik TINGKATAN 5

Penjanaan dan Penghantaran Tenaga Elektrik
3.5 The Generation and Transmission of Electricity

Pelbagai kaedah penghasilan tenaga elektrik dan kesan kepada persekitaran (kebaikan dan keburukan)
Various ways of generating electricity and their effects on the environment (advantages and disadvantages)

Jenis Kebaikan Keburukan
Type Advantages Disadvantages

1 Stesen janakuasa terma / Thermal power stations (i) Boleh (i) Pencemaran udara :
membangunkan
Gas buangan panas Talian penghantaran sebuah Pembakaran bahan api menghasilkan
bandar baru
Hot waste gases Transmission lines (menggunakan asap, habuk dan asid toksik di udara.
arang batu,
Wap air panas Stim bertekanan petroleum) Air pollution:

Hot water vapour tinggi pada 800oC Can develop a new
town (using coal,
Relau High pressure petroleum) Burning of fuels produces smoke, dust and
bagas
steam at 800oC Gegelung toxic acid in the air.

Furnace Turbin pemegun
Turbines Stator coils
Hujan asid
Rotor (ii) :
Rotor
Pembakaran bahan api juga

Air penyejuk Pendandang Pam Transformer injak naik menghasilkan gas berasid seperti sulfur
dibuang semula Pump Step-up transformer
ke sungai atau Boiler (ii) Bahan buangan dioksida dan nitrogen oksida. Gas ini
laut Penjana boleh dikitar
Cooling water Pam Stim tekanan Generator semula (biojisim) larut dalam air dalam atmosfera untuk
Pump rendah dari
discharged back turbin Air penyejuk daripada sungai Can recycle the membentuk asid yang menyebabkan
Low pressure atau laut waste matter
into river or sea Cooling water from river or sea (biomass) hujan asid.
steam from
(iii) Memerlukan Acid rain :
turbines bahan radioaktif
yang kecil Burning of fuels also produce acidic gases
(a) Bahan api seperti arang batu, petroleum, gas asli dan UNIT 3
uranium digunakan dalam stesen janakuasa terma. Small amount such as sulphur dioxide and nitrogen
Fuels such as coal, petroleum, natural gas and uranium of radioactive is
are used in the thermal power stations. required oxides. These gases dissolve in water in

the atmosphere to form acids which results

in acid rain.

(b) Tenaga haba dihasilkan oleh pembakaran arang batu (iii) Kesan rumah hijau :
atau minyak dalam relau atau dari pembelahan nukleus
uranium dalam teras reaktor nuklear. Karbon dioksida berlebihan di atmosfera

Heat energy is produced by burning coal or oil in a furnace menyebabkan suhu yang lebih tinggi
or from the fission of uranium nuclei in the core of a
nuclear reactor. terhasil di persekitaran.

Greenhouse effect:

The excessive carbon dioxide in the

(c) Air menyerap tenaga haba di dalam relau atau penukar atmosphere raises the temperature in the
haba dan bertukar menjadi stim pada tekanan tinggi.
Water absorbs the heat energy in a boiler or heat- environment.
exchanger and is changed into steam at a high pressure.
(iv) Tidak boleh diperbaharui:
(d) Stim bertekanan tinggi menukarkan tenaga haba kepada Bekalan terhad dan boleh habis.
tenaga mekanikal apabila ia memutarkan turbin. Non-renewable:
Their supply is limited and they will
The high-pressure steam converts heat energy into
mechanical energy as it turns the turbine. eventually run out.

(e) Generator menukarkan tenaga mekanikal kepada tenaga (v) Mahal. / Expensive.
elektrik.
(vi) Kesan sinaran radioaktif yang
The generator converts the mechanical energy into merbahaya kepada manusia dan
electrical energy. persekitaran.

(f) Kecekapan: 30% – 35% tenaga yang disimpan di dalam Harmful effects of radioactive radiation on
bahan api ditukarkan kepada tenaga elektrik. humans and environment.

Efficiency: 30% – 35% of the energy stored in the fuel is (vii) Berbau busuk:
transformed into electrical energy. Satu bau busuk dilepaskan daripada
biomass.

Bad odour (smell):
A bad odour is released from the biomass.

115 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Jenis Kebaikan Keburukan
Type Advantages Disadvantages

2 Stesen kuasa hidroelektrik / Hydroelectric power station (i) Bersih dan tidak (i) Mengganggu keseimbangan
membebaskan ekosistem di persekitaran.
Talian penghantaran Empangan Air simpanan bahan cemar ke Satu kawasan hutan yang
Transmission lines Dam Stored water persekitaran. besar perlu dimusnahkan
termasuk flora dan fauna.
Penjana Clean and does not
Generator emit pollutants to Disturbs the equilibrium of the
the environment. ecosystem in the environment.
A large area of forest land has
Air Turbin (ii) Boleh . to be destroyed, including flora
Water Turbines diperbaharui. and fauna.

Renewable (ii) Mengancam / menyesarkan
penduduk tempatan
(a) Stesen hidroelektrik tidak perlu memanaskan stim. (iii) Boleh
In hydroelectric stations, there is no need to heat steam at all. membangunkan Threatens / Displaces local
kawasan rekreasi. population.
(b) Air dikumpul dalam takungan (empangan) yang tinggi dan
mempunyai tenaga keupayaan graviti yang tinggi. Can develop a (iii) Perbelanjaan tinggi.
recreation area. High cost.
Water is collected in a high reservoir and possesses high gravitational
potential energy. (iv) Mengawal banjir.
Control flood.

3UNIT (c) Apabila air itu mengalir melalui paip, tenaga keupayaan graviti ini
bertukar kepada tenaga kinetik . / When the water flows through a
pipe, its gravitational potential energy is changed to kinetic energy.

(d) Tenaga kinetik ditukar kepada tenaga elektrik semasa air yang
mengalir memutarkan bilah turbin. / The kinetic energy of water
is changed to electrical energy when the water turns the blades of a
turbine.

3 Tenaga solar boleh berubah kepada tenaga elektrik (i) Bersih dan tidak (i) Memerlukan ruang
melalui dua kaedah: / Solar energy can be converted into membebaskan
electrical energy by two methods: bahan cemar ke yang besar untuk
(i) Relau suria/Solar furnace persekitaran.
mengumpulkan cahaya
Titik fokus Clean and does not
Focal point emit pollutants to matahari.
the environment.
Cahaya matahari Requires a large
Sunlight (ii) Boleh
diperbaharui. area to collect the Sun’s rays.

Pemantul paraboloid cekung Renewable. (ii) Kecekapan penukaran
Concave paraboloidal reflector adalah agak rendah (kira-
(iii) Percuma. kira 5%) dan harga untuk
(a) Pemantul parabola cekung digunakan untuk memfokus Free. menghasilkan sel solar agak
mahal. / The efficiency of
dan menumpukan tenaga haba dari matahari. / A concave conversion is quite low (about
KToedsoimsteesmticpherpomaatadwrniaaaatbsenroatislryahsteerametfleencteorrgycafrnoTPbmreaennutsuhtpuseaperSesdtinrunatatnncorso.mkvfpeoaratcraeuhnassriiand concentrate the 5%) and the solar cells are
expensive to produce.
Sunlight
(iii) Keamatan sinaran matahari
(b) Tenaga haba digunakan untuk menghasilkan stim yang dikumpulkan tidak
konsisten, dan ini bergantung
yang mempunPeynaeibattenaga kinPaenteilkpednayneradpigunakan untuk kepada cuaca dan masa.
memutarkan tInusrublaitnionbagi penAbjsaonrbaineglpeaknetrl ik.
CAoirldsewjau tkerminasTuhke heat energyPiasmused to produce steam. The high kinetic The intensity of Sun’s rays
energy of this stePaummp is used to drive the turbine of an electrical collected is not consistent as
this depends on the weather
generator. conditions and the time of day.

Sinar matahari
Penutup kaca Sunlight
Glass cover

Sesentuh Output
grid logam Output

Metal grid
contact

© Nilam Publication Sdn. Bhd. Sesentuh logam 116
Metal contact

Silikon jenis-N Silikon jenis-P
P-type silicon
N-type silicon

MODUL • Fizik TINGKATAN 5

Jenis Titik fokus Kebaikan Keburukan
Type Focal point Advantages Disadvantages

Ke sistem pemanas air Cahaya matahari (i) Memerlukan kawasan
To domestic hot water system Penutup transparensSiunlight luas
Transparent cover
untuk membina turbin
Sinar matahari angin.
Sunlight Requires a large
area to construct a wind
PInesnuelabtaiotPCneomncaanvteupl aphPraaaerbbarmobaloouhlikiodtaaiadamlncreepfkleeuncnytogerrap turbine.
(ii) Kelajuan putaran
Air sejuk masuk Pam Black heat-absorbing pemutar turbin tidak
Cold water in Pump konsisten, bergantung
surface kepada keadaan.
Ke sistem pemanas air Penutup transkparensi The speed of rotation of
Transparent cover the rotor is not consistent,
To domestic hot water system depending on weather
conditions.
Sinar matahari
(c) Panel solar menggunakan tenaga matahSaurniliguhnt tuk menjana
tenaga terma untuk memanaskan air di rumFToiatcihkal.fpookiunst
energPIynestnuoelabgtaioet nnerate thPeanreml paelneynerearpgy to heat
Solar panels use sun
Pam AbsorbinCgaphaanyeal matahari
waAteirr saejtuhk ommaseu.k Sunlight

Cold water in Pump

(ii) Sel solar / Solar cell

Sinar matahari

Penutup kaca Sunlight Pemantul paraboloid cekung
Glass cover Concave paraboloidal reflector

Sesentuh

grid logam Output

Ke siscMteoemnttaaplcegtmridanas air Penutup trOanustkpputarensi
To domestic hot water system Transparent cover

Silikon jenis-N Silikon jenis-P SeseSnintuahr mloagtaamhari UNIT 3
N-type silicon P-tPyepneesbilaitcon MetSaul ncolingthatct

Insulation Panel penyerap
Absorbing panel

(a) SmCAeoierlldnssewgojaualtkerarumrihnadskiuapknerdb.uga.et .daapriapbaPPidlauamamptbeardheadnashemkeipkaodnaduckahtoaryyaamngatmahaanrai.

Solar cells are made of semiconductor materials which develop

an e.m.f. when expoSsienadr tmoatsauhnarliight.
Penutup kaca Sunlight

Glass cover

(b) pSeemlSgsraeoisdnelanalotsrughadamiirgudnanaksaantedliatl.a/mSoklaalrkcuellaltsoarO,reulatpumustepdu,injacmalctaunlagtaonrs,,

lamMpest,alwgrriidst watches,Twuarbtienrahnegainters anOduitpnutsatellites.
contact
Wind turbine

4 Tenaga angin / Wind energy Sesentuh logam (i) Bersih dan tidak
Metal contact membebaskan
bahan cemar ke
Silikon jenis-N Silikon jenis-P persekitaran.
P-type silicon
N-type silicon Clean and does not
emit pollutants to the
environment.

Turbin angin (ii) Boleh diperbaharui.
Renewable.
Wind turbine
(iii) Percuma.
Tenaga kinetik angin memutarkan bilah yang dihubungkan kepada Free.
pemutar penjana elektrik untuk menghasilkan tenaga elektrik.

The kinetic energy of wind rotates blades connected to the rotor of an
electrical generator to produce the electrical energy.

(iii) Membebaskan bunyi
bising. / Produces noise.

117 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Jenis Kebaikan Keburukan
Type Advantages Disadvantages

5 Tenaga ombak / Wave energy (i) Bersih dan tidak (i) Memerlukan kos
membebaskan
Permukaan ledakan bahan cemar ke tinggi untuk
Boom persekitaran.
Keseimbangan apungan membina dan mengekalkan
Ombak Balancing float Clean and does not
Waves emit pollutants to the generator gelombang.
environment.
Needs high cost
(ii) Boleh diperbaharui.
Gerakan berombak Renewable. to build and maintain the wave
Rocking motion
(iii) Percuma. generators.
Free.
(ii) Sangat mudah rosak dan susah
dipertahan.

Very vulnerable and difficult to
protect from damage.

3UNIT ‘Salter duck’ ialah bentuk khas yang terapung dan bergolek ke
depan dan ke belakang apabila ombak menghentam ke atasnya.
Gerakan berombak boleh digunakan untuk memacu turbin dan
menjana arus elektrik. Kesemua penjana tenaga mempunyai
barisan 'salter duck' yang lurus menghadap ombak yang datang.
The ‘salter duck’, is a specially shaped float which rocks back and
forth as the waves strikes it. This rocking motion can be used to
drive a turbine and generates electricity. The whole wave energy
generator has a row of ducks lined up facing the on coming waves.

Penghantaran Tenaga Elektrik
Transmission of Electricity

(i) Tenaga elektrik dihantar pada beza keupayaan yang tinggi dan menggunakan arus ulang-alik .
Electrical energy is transmitted at a high voltage and uses an alternating current.

(ii) Transformer injak naik yang menaikkan beza keupayaan pada voltan lampau tinggi iaitu 110 000 V atau 132 000 V. Beza

keupayaan yang ditingkatkan akan menyebabkan penghantaran kuasa dengan arus kecil .

A step-up transformer which increases the voltage to as high a voltage as 110 000 V or 132 000 V. The high voltage will cause the

power to be transmitted with a small current .

(iii) Transformer injak turun digunakan untuk menurunkan beza keupayaan sebelum dihantar kepada pengguna.

Step-down transformers are used to lower the voltage before delivering to the consumers.

© Nilam Publication Sdn. Bhd. 118

MODUL • Fizik TINGKATAN 5

Tenaga yang hilang dalam kabel Sistem Rangkaian Grid Nasional Isu Penghantaran
penghantaran tenaga elektrik dan The National Grid network Transmission Issues
kelebihan penghantaran voltan tinggi
The energy loss in electricity transmission

cables and the advantage of high
voltage transmission

(i) Kesan pemanasan yang disebabkan Supergrid (275 kV • Penghantaran melalui bawah
oleh rintangan kabel menyebabkan /400 kV) tanah atau di atas tanah
kehilangan tenaga elektrik sebagai Overhead or underground
Grid
tenaga haba . (132 kV)
The heating effect due to the resistance
Stesen kuasa Transformer Transformer (i) Kabel voltan lampau tinggi
of the cable causes loss of electrical Power station (25 kV/275 kV (275 kV/400 kV adalah cara yang lebih
energy as heat energy . 25 kV /400 kV) /132 kV) murah untuk menghantar
kuasa pada jarak yang jauh.
(ii) Apabila arus mengalir dalam Industri berat Industri ringan Bandar, kampung dan
kabel, kehilangan kuasa, P, melalui Heavy industry Light industry ladang Extra high voltage cables is
pemanasan adalah: (11 kV) Towns, villages and farms the cheapest way of sending
(33 kV) (415 V/240 V) power over long distances.
When a current flows in a cable, the
power loss, P, through heating is: Transformer Transformer Transformer (ii) Untuk mengelakkan
P = I2R (132 kV/ (33 kV/ (11 kV/415 V/240 V) percikan elektrik, cara yang
33 kV) 11 kV) berkesan ialah menyalut
penebat pada kabel untuk
(iii) Kuasa yang hilang boleh dikurangkan • Rangkaian Grid Nasional merupakan satu sistem memastikan ruang udara UNIT 3
dengan: rangkaian kabel voltan lampau tinggi dalam yang besar di sekeliling
satu rangkaian tertutup menghubungkan semua mereka.
The power loss can be reduced by: stesen kuasa utama di negara ini dengan semua
pengguna utama seperti rumah, pejabat, bandar- To prevent sparkling, the
(a) mengurangkan bandar dan kilang-kilang. effective way is to insulate
rintangan kabel The National Grid Network is a network system the cables to keep huge air
of extra high voltage cable transmission lines space around them.
reducing the resistance of which connects all the major power stations in the
the cables country with all the major users such as homes, (iii) Kabel perlu digantung pada
offices, cities and factories. tiang.
(b) mengurangkan arus mengalir
dalam kabel The cables have to be
suspended from pylons.
reducing the current in the cables

(iv) Oleh itu, untuk mengurangkan • Tenaga elektrik dijanakan di stesen kuasa di • Kos kabel
rintangan kabel, wayar kabel tebal mana beza keupayaan ditingkatkan dengan Cost of cables
digunakan, contoh: wayar kuprum
atau aluminium. menggunakan transformer injak naik kuprum

In order to reduce resistance of the untuk mengurangkan arus yang mengalir (i) Kabel
cables, a thick cable is used e.g copper
or aluminium. melalui grid. Ini mengurangkan kehilangan mempunyai rintangan

kuasa dalam kabel semasa penghantaran. rendah tetapi kos yang

Electrical energy is generated in power stations tinggi.

(v) Kuasa yang dihantar melalui kabel where its voltage is increased by using a Copper cables
ialah P = I V.
step-up transformer to reduce the power have low resistance but high
The power transmitted by the cables is
P= I V. loss in the cables during transmission by lowering cost.

the current flowing through the grid. (ii) Kabel aluminium sering
digunakan kerana ia ringan,
(vi) Maka, arus, I, yang mengalir melalui • Di substesen, sebelum penghantaran kepada rintangannya rendah dan
pelbagai pengguna, voltan lampau tinggi kosnya lebih rendah.
kabel: Aluminium cables are usually
used as they are light, have
So, the current, I, flows in the cables: dikurangkan dengan menggunakan low resistance and its cost
P is low.
I= V transformer injak turun.

(vii) Ini bermaksud, arus, I yang At sub-stations, before reaching the various

consumers, the high voltage is reduced

mengalir melalui kabel adalah by using step-down transformers.

berkadar songsang dengan
beza keupayaan.
This means that the current in the cables

is inversely proportional to the
voltage.

119 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

Kebaikan Sistem Rangkaian Grid Nasional • Kebocoran cas antara kabel
Advantages of the National Grid Network System dengan bumi
Charge leakage between the cables
1 Mudah dikendalikan / Easy to manage
and the earth

Penjanaan tenaga elektrik boleh dikawal dan (i) Untuk mengelak kebocoran
dilaraskan mengikut keperluan pada masa-masa cas, kabel aluminium elektrik
tertentu. disokong oleh menara kawat
Regional control and switching centres enable power to
be sent where and when it is needed. yang tinggi .

2 Pembekalan tenaga elektrik berterusan tanpa To prevent charge leakage, the
gangguan / Continuous supply of electricity
aluminium cables are supported
Apabila kawalan serantau dan pusat pensuisan
membenarkan beberapa stesen dalam rangkaian by high metal
tertutup memutuskan rangkaiannya untuk kerja-kerja
penyelenggaraan, pengguna masih dapat bekalan pylons.
tenaga daripada bekalan penjana lain.
While regional control and switching centres allow • Merbahaya jika disambar petir
some stations and lines to be shut down for maintenance Danger of being struck by lightning
work, consumers still get energy supply from other
3UNIT generator supplies. (i) Kabel ditebat dengan porselin
dan kaca supaya kabel
3 Mengurangkan kos penjanaan tersebut tidak bersentuhan
Reducing cost of generation dengan menara kawat
elektrik.
Penghantaran voltan lampau tinggi boleh The cables are properly fixed
mengurangkan kuasa yang hilang dalam kabel with porcelain and glass
penghantaran. Kos penghasilan elektrik dapat support so that the cables do
dikurangkan. not touch the pylons.
High voltage transmission can reduce the power loss in
transmission cables. The cost of production is reduced. • Merbahaya jika dilanggar oleh
pesawat ringan
Danger of being struck by light
aircraft

4 Mudah untuk dikawal dan diselenggara (i) Lampu dan penanda khas
Easy to control and regulate mesti dipasang pada menara
kawat elektrik itu.
Semasa penggunaan tenaga elektrik yang tinggi, Lights and special markers
lebih banyak penjana boleh dihidupkan. Tetapi must be attached to the pylons.
semasa permintaan pengguna kurang, sebahagian
penjana boleh dipadamkan.
At peak periods of electricity usage, more generators
can be switched on. During periods of low demand,
some generators can be turned off.

© Nilam Publication Sdn. Bhd. 120

MODUL • Fizik TINGKATAN 5

Latihan / Exercise

1 Stesen kuasa menjana 40 kW kuasa elektrik menggunakan rangkaian penghantaran tenaga berintangan

8 Ω. Berapakah kehilangan kuasa semasa penghantaran akibat rintangan kabel jika tenaga elektrik dihantar pada

A power station generates 40 kW of electric power using a power transmission line with resistance of 8 Ω. What is the power
KBAT dissipated due to the resistance of the transmission cables when the current is transmitted at

(a) 5 000 V (b) 20 kV

Penyelesaian / Solution

(a) Hitungkan nilai arus dalam kabel, I (b) P = I V
Calculate value of current in the cable, I
40 × 103 W = I × (20 × 103) V

Kuasa dihantar melalui kabel, P = IV I = 4200 × 103 W
× 103 V
The power transmitted by the cable, P = IV
= 2 A
40 × 103 W = I × 5 000 V

I = 40 × 103 W Maka, kuasa yang hilang disebabkan rintangan,
5 000 V So, the power loss due to the resistance,
= 8 A P = I 2R
= (2 A)2 × 8 Ω
Maka, kuasa yang hilang disebabkan rintangan, = 32 W
So, the power loss due to the resistance,
P = I 2R
= (8 A)2 × 8 Ω
= 512 W

2 Stesen kuasa menjana 80 MW kuasa elektrik pada beza keupayaan 80 kV a.u. melalui rintangan kabel 5 Ω. UNIT 3
A power station generates 80 MW of electric power at a voltage 80 kV through a cable of resistance 5 Ω. Determine:
(a) kuasa yang hilang semasa penghantaran tenaga melalui kabel.

KBAT the power loss in the transmission cable.
(b) peratus kuasa yang hilang. / the percentage of the power loss.
(c) kecekapan penghantaran kuasa. / the efficiency of the power transmission.
(d) pengurangan beza keupayaan di dalam kabel. / the voltage drop in the cable.
Penyelesaian / Solution

(a) Hitungkan nilai arus dalam kabel, I (c) Tenaga dihantar = Kuasa dibekal – Kuasa hilang
Calculate value of current in the cable, I
Power transmitted = Power supply – Power loss

Kuasa yang dihantar oleh kabel, P = IV = 80 × 10 6 W – 5 × 10 6 W

The power transmitted by the cable, P = IV = 75 × 10 6 W

80 × 10 6 W = I × (80 × 103 V) Kecekapan / So, efficiency = 75 × 10 6 W × 100%
80 × 10 6 W
I = 80 × 10 6 W
80 × 10 3 V = 93.75%

= 1 000 A (d) Pengurangan voltan / Voltage drop = IR

Oleh itu, kuasa hilang akibat rintangan, = 1 000 A × 5 Ω
So, the power loss due to the resistance
P = I 2R = 5 000 V
= (1 000 A)2 × 5 Ω
= 5 × 10 6 W

(b) Peratus kuasa hilang

Percentage of power loss

= 5 × 10 6 W × 100%
80 × 10 6 W

= 6.25%

121 © Nilam Publication Sdn. Bhd.

3UNITMODUL • Fizik TINGKATAN 5 3 Rajah 3 menunjukkan corak medan magnet apabila arus
mengalir dalam satu dawai lurus.
L atihan Pengukuhan / Enrichment Exercise Diagram 3 shows a magnetic field pattern when currents
flows in a straight wire.
1 Rajah 1 menunjukkan susunan radas untuk mengkaji
corak medan magnet yang terbentuk apabila arus elektrik Dawai
mengalir dalam konduktor. Wire
Diagram 1 shows an arrangement of apparatus to study the
pattern of magnetic fields which are formed when the current P
flows through conductors.
Q
6V 6V Kompas
Compass
Kadbod
Cardboard Rajah 3 / Diagram 3
Antara berikut, yang manakah menunjukkan arah medan

Rajah 1 / Diagram 1 magnet yang betul bagi kompas P dan Q?
Corak medan magnet yang manakah terbentuk pada Which of the following shows the correct direction of magnetic
field for compass P and Q?
kadbod apabila kedua-dua suis dihidupkan?
Which magnetic fields pattern is formed on the cardboard PQ
when both switches are closed?
A A

B

C B
D C
D

2 Rajah 2 menunjukkan sebatang magnet bersebelahan 4 Rajah 4 menunjukkan sebuah transformer ringkas.
dengan suatu gegelung. Petunjuk galvanometer terpesong Diagram 4 shows a simple transformer.
semasa magnet itu ditolak ke dalam gegelung. / Diagram 2
shows a coil of wire placed next to a magnet. The galvanometer Teras besi lembut
pointer deflects when the magnet is pushed into the coil. Soft iron core

Input Output
240 V 6V

Rajah 2 / Diagram 2 Gegelung primer Gegelung sekunder
Primary coil Secondary coil
Tindakan yang manakah akan menambahkan pesongan
petunjuk galvanometer itu? Rajah 4 / Diagram 4
Which action will increase the deflection of the galvanometer
pointer? Arus dalam gegelung primer ialah 0.1 A dan kecekapan
A Kutub magnet itu disongsangkan transformer itu ialah 60%. Kuasa output transformer itu
The magnet pole is reversed ialah
B Bilangan lilitan gegelung itu ditambah The current in the primary coil is 0.1 A and the efficiency
The number of coil is increased of the transformer is 60%. The output power of the
C Gegelung dibuat daripada wayar yang bertebat transformer is
The coil is made from insulated wire
D Magnet itu ditolak perlahan-lahan ke dalam gegelung A 6.0 W
The magnet is pushed slowly into the coil B 14.4 W
C 24.0 W
D 40.0 W

© Nilam Publication Sdn. Bhd. 122

MODUL • Fizik TINGKATAN 5

5 Rajah 5 menunjukkan dua magnet, J dan K, tergantung 7 Rajah 7 menunjukkan struktur binaan motor elektrik.
bebas di kedua-dua hujung solenoid. Diagram 7 shows the structure of an electric motor.

Diagram 5 shows two magnets J and K, hang freely at both NS
ends of the solenoid.

NS SN Rajah 7 / Diagram 7
Corak medan magnet yang manakah betul apabila suis
Magnet J Magnet K
Magnet J Magnet K lampu dihidupkan?
Which of the magnetic field patterns is correct when the motor
Rajah 5 / Diagram 5 is switched on?
A
Pemerhatian manakah yang betul apabila suis dihidupkan?
Which observation is correct when the switch is turned on? B

Magnet J Magnet K C

Bergerak menjauhi Bergerak mendekati D

A solenoid / Moves away solenoid / Moves

from the solenoid towards the solenoid

Bergerak menjauhi Bergerak menjauhi

B solenoid / Moves away solenoid / Moves away UNIT 3

from the solenoid from the solenoid

Bergerak mendekati Bergerak mendekati
C solenoid / Moves solenoid / Moves
towards the solenoid
towards the solenoid

Bergerak mendekati Bergerak menjauhi
D solenoid / Moves solenoid / Moves away
from the solenoid
towards the solenoid

6 Rajah 6 menunjukkan sebiji mentol 24 V, 18 W menyala 8 Penghantaran elektrik disalurkan pada voltan yang sangat
pada kecerahan normal. / Diagram 6 shows a bulb 24 V, 18 tinggi supaya
W lights up with normal brightness. Electricity is transmitted at a very high voltage in order to
A meningkatan arus dalam kabel
Input 24 V, 18 W increase the current in the cables
Input B mengurangkan rintangan kabel
reduce the resistance of the cables
240 V Output C mengurangkan kehilangan kuasa
Output reduce power loss
Bilangan lilitan = 100 D menambahkan rintangan kabel
Number of turns = 100 Bilangan lilitan = 10 increase the resistance of the cables
Number of turns = 10

Rajah 6 / Diagram 6 9 Berapakah kehilangan kuasa dalam kabel penghantaran
apabila 50 kW dihantar melalui kabel yang berintangan
Apakah yang akan berlaku kepada mentol apabila bilangan 4.0 Ω pada voltan 10 kV?
lilitan pada gegelung sekunder ditambah kepada 50 lilitan? What is the power loss in a transmission cable when 50 kW
What will happen to the bulb when the number of turns in is transmitted through a cable with a resistance of 4.0 Ω at a
secondary coil increases to 50 turns? voltage of 10 kV?
A Malap / Dimmer
B Lebih terang / Brighter A 5 W C 100 W
C Terbakar / Blown up B 25 W D 200 W
D Kecerahan tidak berubah
The brightness unchanged

123 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

S oalan Struktur / Structure Questions

1 Rajah 1.1 menunjukkan sebuah transformer unggul yang disambung kepada motor elektrik 12 V, 40 W a.u. Motor ini berfungsi
secara normal.
Diagram 1.1 shows an ideal transformer which is connected to a 12 V, 40 W a.c. electric motor. This motor functions normally.

240 V a.u. Gegelung Gegelung M Motor elektrik
240 V a.c. primer sekunder Electric motor
Primary Secondary
coil coil

Np = 1 200 lilitan / turns

Rajah 1.1 / Diagram 1.1
(a) Nyatakan jenis transformer yang digunakan.
State the type of transformer used.

Transformer injak turun. / Step-down transformer.

(b) (i) Hitung bilangan lilitan gegelung sekunder itu. / Calculate the number of turns of the secondary coil.

—NS– = —VS–
NP VP

NS = —VS– × NP
VP

3UNIT = —214—20V–V– × lilitan / turns

= 60 lilitan / turns

(ii) Hitung arus yang mengalir dalam gegelung primer itu.
Calculate the current flow in the primary coil.

Kuasa output / Output power = 40 W

∴ Kuasa input / Input power = 40 W (Untuk transformer unggul / for idea transformer)

∴ PP = 40 W, VP = 240 V

PP = VP IP

∴ IP = —PP–
VP

= —40—W––
240 V

= 0.1667 A

= 0.17 A

(c) Rajah 1.2 menunjukkan transformer yang sama disambungkan kepada sebuah komponen elektrik dalam kotak Y untuk
menyalakan sebuah mentol a.t.

Diagram 1.2 shows the same transformer being connected to an electrical component in box Y to light up a d.c. bulb.

Y

240 a.u. Gegelung Gegelung M Motor elektrik
240 a.c. primer sekunder Electric motor
Primary Secondary
coil coil

Rajah 1.2 / Diagram 1.2

Namakan komponen elektrik dalam kotak Y. / Name the electrical component in box Y.

Diod. / Diode.

© Nilam Publication Sdn. Bhd. 124

MODUL • Fizik TINGKATAN 5

2 Rajah (a) dan Rajah (b) menunjukkan sistem penghantaran elektrik yang menghubungkan stesen penjana kuasa dan pengguna
melalui suatu jarak tertentu./ Diagram (a) and Diagram (b) show the electricity transmission system connecting the electric power
generating stations and the user through a certain distance.

Kabel aloi aluminium / Aluminium alloy cable

135 kV

Stesen penjana kuasa Transformer Pilon Transformer Pengguna
Power generator station injak-naik Pilion injak-turun User
Step-up Step-down
20 MW transformer Rajah (a) / Diagram (a) transformer 18 MW

Kabel aloi aluminium / Aluminium alloy cable
120 kV

Stesen penjana kuasa Transformer Pilon Transformer Pengguna
Power generator station injak-naik Pilion injak-turun User
Step-up Step-down
20 MW transformer Rajah (b) / Diagram (b) transformer 15 MW

(a) Lengkapkan jadual di bawah dengan membandingkan aspek-aspek yang dinyatakan: UNIT 3
Complete the table below by comparing the aspects mentioned:

Aspek Rajah (a) Rajah (b)
Aspect Diagram (a) Diagram (b)

Voltan pada kabel penghantaran Lebih besar Lebih kecil
The voltage on the transmission cable
Larger Smaller

Arus dalam kabel penghantaran Lebih kecil / Smaller Lebih besar / Larger
The current in the transmission cable (148.15 A) (166.67 A)
Guna formula P = IV untuk mencari I
Use the formula P = IV to find I

Rintangan kabel penghantaran Sama Sama
The resistance of transmission cable Same Same

Kehilangan kuasa semasa penghantaran Lebih kecil / Smaller Lebih besar / Larger
The loss of power during transmission
(20 MW – 18 MW = 2 MW) (20 MW – 15 MW = 5 MW)
Kuasa yang sampai kepada pengguna (Kuasa output)
The power that reaches the consumer (Output power) Lebih besar / Larger Lebih kecil / Smaller

(18 MW) (15 MW)

Kuasa input Sama Sama
The input power Same Same

Kecekapan sistem penghantaran elektrik Lebih cekap Kurang cekap
The efficiency of electricity transmission system More efficient Less efficient

125 © Nilam Publication Sdn. Bhd.

MODUL • Fizik TINGKATAN 5

(b) Hubung kaitkan: / Relate:
(i) voltan pada kabel penghantaran dan arus dalam kabel penghantaran
the voltage on the transmission cable and the current in the transmission cable

Semakin bertambah voltan pada kabel penghantaran, semakin berkurang arus dalam kabel penghantaran

As the voltage on the transmission cable increases, the current in the transmission cable decreases

(ii) arus dalam kabel penghantaran dan kehilangan kuasa semasa penghantaran
the current in the transmission cable and the loss of power during the transmission
Semakin berkurang arus dalam kabel penghantaran, semakin berkurang kehilangan kuasa semasa penghantaran
As the current in the transmission cable decreases, the loss of power during the transmission decreases

(iii) arus dalam kabel penghantaran dan kecekapan sistem penghantaran
current in transmission cable and efficiency in transmission system
Semakin berkurang arus dalam kabel penghantaran, semakin bertambah kecekapan sistem penghantaran
As current in transmission cable decreases, effiency of transmission system increase

3UNIT (c) Pemboleh ubah:
Variables:

(i) Dimanipulasikan / Manipulated : Arus dalam kabel, I / Current in the cable, I

(ii) Bergerak balas / Responding : Kehilangan kuasa, P / Loss of power, P

(iii) Dimalarkan / Constant : Rintangan kabel, R / Resistance of cable, R

Memahami teori melalui pendekatan matematik:
Understanding the theory through the mathematical approach:

Kehilangan kuasa, P[$] = (I [$])2R[malar]
Power loss, P[$] = (I [$])2R[constant]

Kuasa output[#] = Kuasa input[malar] − Kehilangan kuasa[$]
Output power[#] = Input power[constant] – Power loss[$]

Kecekapan[#] = Kuasa output[#] × 100%
Kuasa input[malar]

Efficiency[#] = Output power[#] × 100%
Input power[constant]

Apabila rintangan kabel, R, tetap, kehilangan kuasa, P, bergantung pada arus dalam kabel, I Maklumat tambahan:
When the resistance of cable, R is constant, the power loss, P depends on the current in the cable. I Additional information:

Semakin berkurang arus dalam kabel, I, semakin berkurang kehilangan kuasa, P (P α I2)
As the current in the cable, I decreases, the power loss, P decreases (P α I2)

Semakin berkurang kehilangan kuasa, semakin bertambah kuasa output
As the power loss decreases, the output power increases

Untuk kuasa input yang tetap, kecekapan bergantung pada kuasa output
When the input power is constant, efficiency depends on the input power

Semakin bertambah kuasa output, semakin bertambah kecekapan (Kecekapan α Kuasa output)
As the input power increases, the efficiecny increasses (Efficiency α Output power)

© Nilam Publication Sdn. Bhd. 126