Modul Fizik SPM Kertas 2 & 3

Bab 7: Elektrik Chapter 7: Electricity

Diagram 10.3 shows a simple structure of bulb. The bulb working based on heating of filament
depends on their resistance, but does not produce brighter light.
Rajah 10.3 menunjukkan satu struktur ringkas mentol. Mentol itu bekerja berdasarkan pemanasan
filamen bergantung kepada rintangannya, tetapi tidak menghasilkan cahaya yang lebih cerah.

Diagram 10.3 Rajah 10.3

(d) The bulb in Diagram 10.3 is going to be used to light up at larger area.
Explain the modification need to be done to the bulb to increase the brightness to light up at larger
area. In your explanation, emphasize the aspects of:
Mentol dalam Rajah 10.2 itu akan digtmakan untuk menerangi kawasan yang lebih luas.
Terangkan pengubahsuaian perlu dilakukan kepada mentol itu untuk meningkatkan kecerahan
bagi menerangi pada kawasan yang luas.
Dalam penjelasan anda, berikan penekanan kepada aspek-aspek:

(i) The shape of the filament used.
Bentuk filamen yang digunakan.

(ii) The thickness of the filament wire.
Ketebalan dawai filamen.

(iii) Melting point of the filament material.
Takat lebur bahan filamen.

(iv)Gas pressure inside the bulb.
Tekanan gas di dalam mentol.

(v) Material used for contact points.
Bahan yang digunakan untuk titik-titik penyambung.

[10 markah]

Bab 7: Elektrik Chapter 7: Electricity

BAHAGIAN C

12. Diagram 12.1 shows an electrical circuit.
Rajah 12.1 menunjukkan satu litar elektrik.

Diagram 12.1 Rajah 12.1

(a) (i) What is the function of rheostat in the circuit ? [ 1 mark]

Apakahfungsi rheostat datam litar? [ l markah]

(ii) State the energy transformation occurs at the bulb in the circuit.
Nyatakanperubahan tenagayang berlakupada mentol dalam litar itu [1 markah]

(iii)Based on Diagram 12.1, draw a circuit diagram using symbols.
Berdasarkan Rajah 12.1, lukiskan satu gambarajah litar menggunakan simbol [ 1 Markah ]

(b) Explain why the brightness of the bulb increases when the slider is adjusted close to Q.
Terangkan mengapa kecerahan mentol bertambah apabila gelongsor dilaraskan mendekati Q. [2
markah}

(c) Diagram 12.2 shows an electric circuit consist of two bulbs R and S labeled 6V, 3 W and 6V,
12W respectively connected to a 6V battery.
Rajah 12.2 menunjukkan satu litar elektrik terdiri dari dua mentol, R dan Syang masing-masing
berlabel 6K3Wdan 6V,12W disambungkanpada sebuah bateri 6V.

Diagram 12.2 / Rajah 12.2

Bab 7: Elektrik Chapter 7: Electricity

When the switch is turned on, calculate:
Apabila suis dihidupkan, hitungkan r

(i) the total current flows in the circuit.
Jumlah arus yang mengalir didalam litar. [ 3 markah]

(ii) the energy used by a bulb, R in one minute.
tenagayang digtmakan oleh mentol R dalam satu minit. [2 markah)

(d) National Grid Network is a system of electric transmission from power station to the consumer in
our country. Diagram 12.3 shows a block diagram of the system.
Rangkaian GridNasional ialah satu sistem penghantaran tenaga elektrik daripada stesen
janakuasa ke kawasan pengguna di negara kita. Rajah 12.3 menunjukkan gambarqjah blok sistem
tersehut.

Diagram 12.3 Rajah 12.3

Using your knowledge about electrical and Diagram 12.3 , you are asked to determine the
mastsuitable item used in the system J, K, L, M and N for a National Grid Network system in
Diagram 12.4.
Menggunakan pengetahuan anda mengenai elektrik dan Rajah 12,3, anda dikehendaki
mengenalpasti ciri-ciri yang digtmakan dalam system J, K, L, M dan N untuk Rangkaian Grid
Nasional dalam Rajah 12.4.

System Type of Diameter of Transmission voltage Cable Position
Sistem Transformer Jenis conductor cable Voltan Penghantaran Kedudukan
transformer Diameter
J konduktor kabel kabel
P is step up Q is
K step down P injak Big diameter Curent with low On the jpylon
naik Q injak turun conductor voltage Di atas pilon
Diameter Arus dengan voltan
Q is step up P is konduktor besar rendah On concrete
step down Q injak piller
naik P injak turun Small diameter Current with high Di atas tiang
conductor voltage konkrit
Diameter Arus dengan voltan
konduktor kecil tinggi

Bab 7: Elektrik Chapter 7: Electricity

L P is step up Q is Big diameter Current with high On the pylon

step down P injak conductor voltage Di atas pilon

naik Q injak turun Diameter Arus dengan voltan

konduktor besar tinggi

M Q is step up P is Small diameter Curent with "low On concrete

step down Q injak conductor voltage piller

naik P injak turun Diameter Arus dengan voltan Di atas tiang

konduktor kecil rendah konkrit

N P is step up Q is Small diameter Current with high On concrete

step up P injak naik conductor voltage piller

Q injak naik Diameter Arus dengan voltan Di atas tiang

konduktor kecil tinggi konkrit

Study the specification of the five systems and explain the suitability of each system based on
following aspects:
Kaji spesifikasi kelima-lima sistem itu dan terangkan kesesuaian setiap satunya berdasarkan
aspek berikut.

(i) type of transformer P and Q
jenis transformer P dan Q

(ii) characteristics; of cable used
ciri-ciri kabel yang digunakan

(iii)electrical potential difference trasmitted.
beza keupayaan elektrik yang dihantar

(iv)The position of cable
kedudukan kabel

Explain (he suitability of each aspects and determine the most suitable system. Give your
reason for your choice.
Terangkan kesesuaian setiap aspek dan tentukan sistem yang paling sesuai. Beri sebab bagi
jawapan anda.

[10 markah]

Bab 7: Elektrik Chapter 7: Electricity
Skema Jawapan Bab 7
Suggested answer Mark
Question State the correct physical quantity 1
1 (a) Measures potential difference /voltage 1
(b) (i) State the correct relationship 1
(ii) Increase
State the correct answer 1
(iii) Remain unchanged
4
State the correct physical quantity
Length/temperature/cross-sectional area
/resistivity of conductor /
Total

Question Suggested answer Mark
2 (a) Cross sectional of P > Cross sectional of Q 1
(b) (i)
Gradient of V-l graph 1
(ii)
Draw a triangle 1
(8.0 - 0)/(5 6 - 0) 1
1 = 1.6 ohm//VA” 1
5
Total

Question Suggested answer Mark
3 (a) Parallel circuit 1
(b) (i)
(c) Mk 1 – all symbols correct 2
Mk 2 – circuit is correct 1
(d) The brightness of lamp J = lamp K = lamp L
(e) = lamp M 1
1
The voltage is the same 6
One bulb blow, other bulbs still lights up
Total

Question Suggested answer Mark
4 (a) X : Ammeter 1
Y : Voltmeter 1

Bab 7: Elektrik Chapter 7: Electricity

(b) Directly proportional 1
(i) Ohm’s Law 1
(ii)
(c) Resistance 1
(i) Constantant s.w.g 36 1
(ii) Higher gradient 1
(iii)
Total 7

Question 6 :

Question Mark Description Total Mark
6(a) M1 Is a region in which an electric charge will experience 1
(b) (i) force // region of electrical force
M1 EHT voltage in Diagram 6.1 < Diagram6.2 5
(ii) M1 The strength of electric field in Diagram 6.1 < Diagram 2
(iii) 6.2 8
(iv) M1 The oscillation velocity in Diagram 6.1 < Diagram 6.2
M1 When the EHT voltage increases, the strength of
(v) electric field increases // the EHT voltage is directly
M1 proportional to the strength of electric field
(c) When the strength of electric field increases, the
M1 oscillation velocity increases // the strength of electric
M2 field is directly proportional to the oscillation velocity
Velocity of oscillation increases
Strength of electric field increases

Total mark

7. (a) (i) Series 1

(b) 1. Ammeter reading increase. 1
(c)(i) 2. Effective resistance is smaller 1

(ii) V2 = 9 = 1.5 Ω // atau guna V=IR 1
R6
1
1. Total resistance = 3 Ω 1
2. Current flow = 3V

3Ω

3. I = 1A 1

(iii) Brightness of bulbs in Diagram 7.2 is greater than Diagram 7.3 1

(iv) 1. Bulbs are connected in parallel. 1

2. Circuit is complete, function able, batteries are labelled as 1

3V or draw two batteries in series

Bab 7: Elektrik Chapter 7: Electricity

Bulb 3V, 6W
Bulb 3V, 6W

12 (a) (i) To control resistance / electric current 1
(ii) Electrical energy to heat energy to light energy 1
(iii)

(b) Length of wire decreases 1
(c) (j) Resistance decreases 1
Current increase 1
(ii) P = VI
(d) I= P 1
1
V 1
=3
Reasoning 1
6 P to increase voltage, Q to 1
= 0.5 A decrease voltage to 10
consumer
Total I = 0.5 x 2 = 1 A Reduce resistance
Small current flows //
E = VIt Reduced power/ heat loss
= 6 x 0.5 x 60 Safety reason
= 180 J
Aspect
P step up, Q step down

Big Diameter
Current with high voltage

Cable on pylon

Bab 7: Elektrik Chapter 7: Electricity

L is chosen P step up Q step down, Big
Diameter, Current with high
Total voltage, Cable on pylon

20

Bab 8: Elektromagnet Chapter 8: Electromagnetism

SECTION A

1. Diagram 1.1 shows a light copper rod is placed between two poles of a magnadur.
Current from the bare copper plate flows to the rod when the switch is closed.
Rajah menunjukkan satu rod kuprum ringan diletakkan di antara dua kutub magnet
megnedur. Arus dari plat kuprum tak bertebat mengalir melalui rod apabila suis
ditutup.

(a) i. On Diagram 1.1, mark the direction of the current in the rod. [1 mark]
Pada Rajah 1.1, tandakan arah arus dalam rod.

ii. Determine the direction of the movement of rod. [1mark]
Tentukan arah gerakan rod.
……………………………………………………………………………

(b) Name the physics’ rule to determine the answer in 1(a)(ii).
Namakan peraturan fizik untuk menentukan jawapan dalam 1(a)(ii).

……………………………………………………………………………… [1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(c) State the effect on the movement of the rod when the current is increased.
Nyatakan kesan terhadapgerakan rod apabila arus ditambah.

……………………………………………………………………………………… [1 mark]

2. Diagram 2.1 shows a simple electromagnet.
Rajah 2.1 menunjukkan satu elektromagnet ringkas.

DIAGRAM 2.1
RAJAH 2.1

(a) What is the meaning of electromagnet?
Apakah maksud elektromagnet?

…………………………………………………………………………………..
[1 mark]

(b) When the switch is turned on ;
Bila suis dihidupkan ;
(i) Draw the pattern of magnetic field on Diagram 2.1
lukis corak medan magnet pada Rajah 2.1
[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(ii) state the magnetic pole at P
nyatakan kutub magnet pada P.
……………………………………………………………......................
[1 mark]

(iii) state what happens to the pin.
nyatakan apa yang berlaku kepada pin itu.

…………………………………………………………………………
[1 mark]

(c) State one application of electromagnet.
Nyatakan satu kegunaan elektromagnet.

…………………………………………………………………………………
[1 mark]

3. Diagram 3 shows a bar magnet is being pushed towards a solenoid.
Rajah 3 menunjukkan magnet bar ditolak ke arah solenoid.

(a) What is meant by electromagnetic induction?
Apakah maksud aruhan elektromagnet?

............................................................................................................ .....................................

[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(b) State the polarity at X when the bar magnet is moved towards the
solenoid.
Nyatakan kekutuban pada X apabila magnet bar digerakkan ke dalam
solenoid.

...............................................................................................................................................

[1 mark]

(c) In Diagram 3, when the magnet is pushed towards the solenoid;
Dalam Rajah 3, apabila magnet ditolak masuk ke dalam solenoid;

(i) mark the direction of induced current on the solenoid,
tandakan arah arus aruhan pada solenoid,

(ii) show the direction of the pointer on the zero centred galvanometer.
tunjukkan arah anak panah pada galvanometer sifar tengah.

[2 marks]

(d) State one method to increase the induced current in the solenoid.
Nyatakan satu kaedah untuk meningkatkan arus aruhan di dalam
solenoid.

...........................................................................................................................................

[1 mark]

(e) Name the physics law involved in determining the pole in (b) above.
Namakan hukum fizik yang terlibat dalam menentukan kutub
pada (b) di atas.

........................................................................................................................................

[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

4. Diagram 4 shows an ideal transformer used to light up a bulb labelled 24 V, 36 W.
Rajah 4 menunjukkan sebuah transformer unggul digunakan untuk menyalakan
sebuah mentol berlabel 24 V, 36 W.

Primary coil Soft iron core Secondary coil
Gegelungprimer Terasbesilembut Gegelungsekunder

240 V ac 24 V,36 W
mains supply
Bekalan utama

au240 V

Diagram 4
Rajah 4

When the mains supply is switched on the bulb is very dim.
Apabila suis bekalan utama dihidupkan, didapati mentol sangat malap.

(a) State two ways to increase the brightness of the bulb without changing the
voltage of the mains supply.
Nyatakan dua cara bagi meningkatkan kecerahan mentol tanpa menukarkan
Beza keupayaan bekalan utama.

(i)...………………………………………………………………………………………..

.…………………………………………………………………………………………
[1 mark]

(ii)…………………………………………………………………………………………

…………………………………………………………………………………………

[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(b) Explain why the core is made from soft iron.
Terangkan mengapa teras diperbuat daripada besi lembut.

……………………………………………………………………………………………
[1 mark]

(c) If the light bulb operates at normal brightness,calculate:
Jika mentol beroperasi pada kecerahan normal, hitungkan:

(i) The electric current flowing in the secondary coil.
Arus elektrik yang mengalir dalam gegelung sekunder.

[2 marks]

(ii) The electric current flowing in the primary coil.
Arus elektrik yang mengalir dalam gegelung primer.

[2 marks]

5 Diagram 6.1 and Diagram 6.2 show that a current is induced in a solenoid when a bar
magnet is moved in or out of the solenoid.
Rajah 6.1 dan Rajah 6.2 menunjukkan arus diaruhkan dalam sebuah solenoid apabila
sebatang magnet bar digerakkan masuk atau keluar dari solenoid itu.

Bar magnet Bar magnet
X Y

Magnet bar Magnet bar

NN

DIAGRAM 6.1 / RAJAH 6.1 DIAGRAM 6.2 / RAJAH 6.2

(a) What is meant by induced current?
Apakah yang dimaksudkan dengan arus aruhan?

.........……………………………………………………………………………………
[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(b) Based on the direction of the current in Diagram 6.1 and Diagram 6.2;
Berdasarkan arah arus dalam Rajah 6.1 dan Rajah 6.2;

(i) Label the polarity at the end of each solenoid in box X and box Y.
Label kekutuban di hujung setiap solenoid dalam petak X dan petak Y.

[2 marks]

(ii) Label the direction of motion of the bar magnet in the boxes provided in
Diagram 6.1 and Diagram 6.2
Label arah gerakan setiap magnet bar dalam petak yang disediakan di Rajah
6.1 dan Rajah 6.2.
[2 marks]

(c) (i) State whether the force that acts between the solenoid and bar magnet in
Diagram 6.1 and Diagram 6.2 is attractive or repulsive.
Nyatakan sama ada daya yang bertindak antara solenoid dan magnet bar dalam
Rajah 6.1 dan Rajah 6.2 adalah tarikan atau tolakan.

Force in Diagram 6.1 / Dayadalam Rajah 6.1 : …………….…………………..

Force in Diagram 6.2 / Dayadalam Rajah 6.2 : …………….…………………..
[2 marks]

(ii) Name the law that applies to (c)(i).
Namakan hukum yang digunakan di (c)(i).

.....................……………………………………………………………………..
[1 mark]

(d) Suggest one method to increase the magnitude of the induced current in the solenoid.
Cadangkan satu kaedah untuk menambahkan magnitud arus aruhan dalam solenoid.

.........……………………………………………………………………………………
[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

6 Diagram 6.1 and 6.2 show a bar magnet is pushed into a solenoid at a speed of 2 ms-1.

Rajah 6.1 dan 6.2 menunjukkansebuah magnet bar ditolakmasukkedalam solenoid
dengankelajuan 2 ms-1.

DIAGRAM 6.1 DIAGRAM 6.2

(a) State the physical quantity that is represented by the deflection of the
galvanometer.
Nyatakan kuantiti fizik yang diwakili oleh pesongan galvanometer.

………………………………………………………………………………………

[1 mark]

(b) Based on Diagram 6.1 and Diagram 6.2:
Berdasarkan Rajah 6.1 dan Rajah 6.2:

(i) State two differences that can be observed from Diagram 6.1 and Diagram 6.2.
Nyatakanduaperbezaan yang bolehdiperhatikandalam Rajah 6.1 dan Rajah
6.2.
…………………………………………………………………………………
…………………………………………………………………………………
…………………………………………………………………………………

[2 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(ii) Based on the answer in (b)(i), explain why these differences occur?
Berdasarkan jawapan pada (b)(i), jelaskan mengapa perbezaan ini berlaku?

.............................................................................................................................

............................................................................................................................
............................................................................................................................

[2 marks]

(c) Name the physics law involved in 6(b)(ii).
Namakan hokum fizik yang terlibat dalam 6(b)(ii).

....................................................................................................................................
[1 mark]

(d) Explain why the direction of current in the solenoid is upward as shown in
Diagram 6.1 and Diagram 6.2?
Terangkan mengapa arah arus dalam solenoid keatas seperti yang ditunjukkan

dalam Rajah 6.1 dan Rajah 6.2?

....................................................................................................................................
....................................................................................................................................
....................................................................................................................................

[2 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

7 Diagram 7 shows a fixed coil is placed in between an iron rod and a bar magnet.
Rajah 7 menunjukkan satu gegelung yang tetap diletakkan di antara sebatang rod besi dan
sebuah magnet bar.

When the switch is closed, both of the iron rod and the bar magnet are attracted towards the
coil.
Apabila suis dihidupkan, kedua-dua rod besi dan magnet bar tertarik kepada gegelung.

(a) State the polarity at X.
Nyatakan kutub di X.

............................................................................................................................. ..........
[1 mark]

(b) Suggest two modifications that can be done in Diagram 7 in order to increase the force of
attraction between the coil and the iron rod.
Cadangkan dua pengubahsuaian yang boleh dilakukan dalam Rajah 7 bagi menambahkan
daya tarikan antara gegelung dan rod besi.

.......................................................................................................................................

............................................................................................................................. ..........
[2 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(c) (i) What will happen to the iron rod and the bar magnet when the connections to
the terminals of the battery are reversed?
Apakah akan berlaku kepada rod besi dan magnet bar jika sambungan kepada terminal
bateri diterbalikkan.
.......................................................................................................................................

.......................................................................................................................................

(ii) Explain your answer in 7(c)(i).
Terangkan jawapan anda di 7(c)(i).

............................................................................................................................. ..........

.......................................................................................................................................

[2 marks]

(d) The battery is then replaced by a low alternating current power supply. The switch is then
closed.
Bateri kemudian ditukar dengan bekalan arus ulang-alik yang berkuasa rendah. Suis
dihidupkan.

(i) Describe the motion of the iron rod.
Jelaskan pergerakan rod besi.

.......................................................................................................................................

(ii) Describe the motion of the bar magnet.
Jelaskan pergerakan magnet bar.

.............................................................................................................................................
[1 mark]

(e) Using your answers in 7(c) and 7(d), state one application of iron rod with the coil in
everyday life.
Dengan menggunakan jawapan anda dalam 7(c) dan 7(d), nyatakan satu aplikasi rod besi
bersama gegelung dalam kehidupan harian.

..........................................................................................................................................

[1 mark]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

8 Diagram 8.1 demonstrates the force acting on a current carrying conductor in a magnetic
field
Rajah 8.1 menunjukkan daya yang bertindak pada satu konduktor yang membawa arus
dalam medan magnet.

battery slip ring copper wire

bateri gelang gelincir wayarkuprum

switch

suis SN
Plastic holder N
Pemegangplastik strong permanent magnets

Diagram 8.1/Rmajaaghne8t.1kekal yang kuat

(a) (i) When the switch is closed, what observation can you make?
Apabilasuisditutup, apakahpermerhatian yang dapatandabuat?

………………………………………………………………………………..

[1 mark]
(ii) State the rule which can be used to determine the direction of motion of the

copper wire?
Berikan nama peraturan yang digunakan bagi menentukan arah gerakan
wayar kuprum tersebut ?

………………………………………………………………………………..

[1 mark]

(iii) Draw the pattern of electromagnetic field (catapult field) in the diagram
below.
Lukiskan corak medan elektromagnet (medan lastik) pada rajah di bawah.

SN

[3 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(iv) How can the magnitude of the force be increased?
Bagaimanakah magnitude daya tersebut boleh dipertingkatkan?

………………………………………………………………......……………
[1 mark]

(b) Diagram 8.2 shows an electric motor which is supplied with a direct current
Rajah 8.2menunjukkansebuah motor eletrik menggunakan bekalan arus terus

Diagram 8.2/Rajah 8.2

(i) Explain why the motor will rotate faster when the current increases.
Jelaskanmengapa motor akanberputardenganlebihlajujikaarusbertambah.

………………………………………………………………......……………

………………………………………………………………......……………
[2 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(ii) State two other ways to increase the speed of the motor.
Nyatakan dua lagi carau ntuk menambah laju putaran motor.

………………………………………………………………......……………

………………………………………………………………......……………
[2 marks]

(iii) What will happen when the motor in Diagram 8.2 is connected to the
alternative current (a.c) power supply? Explain.

Apa akan terjadi jika motor dalam Rajah 8.2 disambung dengan bekalan
kuasa arus ulang alik (a.u)? Jelaskan.

………………………………………………………………......……………

………………………………………………………………......……………
[2 marks]

SECTION B

9 The following diagram 1 and Diagram 2 show wire coils connected to the
ammeters, switches and d.c. power supply.
Rajah 1 dan Rajah 2 di bawah menunjukkan gegelung dawai yang
disambungkan kepada ammeter suis dan bekalan kuasa a.t.

Diagram 1 Diagram 2

Bab 8: Elektromagnet Chapter 8: Electromagnetism

When the switch is on and iron filings of the same amount is spread on each
of the cardboard surface, the pattern of the iron filings is formed as shown in
the diagrams.
Apabila suis dihidupkan dan serbuk besi yang sama banyak ditaburkan pada
permukaan setiap kadbod, corak susunan serbuk besi terhasil adalah seperti
yang ditunjukkan dalam kedua-dua rajah tersebut.

(a) What is the meant by magnetic field? [1 mark]
Apakah maksud medan magnet? [3 marks]

(b) Using Diagram 1 and Diagram 2, compare the number of turns of the coils,
the pattern of the iron filings and angle of deflection of the ammeter
indicator.
Menggunakan Rajah 1 dan Rajah 2, bandingkan bilangan lilitan gegelung,
corak susunan serbuk besi dan sudut pesongan penunjuk ammeter.

(c) State the relationship between the strength of the magnetic field and [2 marks]
Nyatakan hubungan antara kekuatan medan magnet dengan

(i) the pattern of iron filings, / corak susunan serbuk besi,
(ii) the number of turn of the coils, / bilangan lilitan gegelung.

(d) Diagram 3 shows two thin copper strips PQ and RS, connected to a circuit. [4 marks]
Rajah 3 menunjukkan dna jalur kuprum nipis, PQ and RS, yang
disambungkan kepada satu litar.

Diagram 3

Bab 8: Elektromagnet Chapter 8: Electromagnetism

Explain what happens to PQ and RS, when the switch is on.
Terangkan apa yang berlaku kepada PQ dan RS apabila suis dihidupkan.

(e) Diagram 4 shows an electric motor which is supplied with a 12 V a.c.
Rajah 4 menunjukkan sebuah motor elektrik yang menggunakan bekalan
kuasa 12V a.u.

Diagram 4 [4 marks]

(i) Explain how the motor is able to rotate.
Terangkan bagaimana motor tersebut boleh berputar

(ii) Using a 12 V a.c. power supply, explain the modification that needs

to be done on the motor and the external circuit to enable motor to be [6 marks]
a d.c. electric motor and rotate faster.

Dengan menggunakan bekalan kuasa 12 V a.u., terangkan

pengubahsuaian ke atas motor itu dan litar luar sup aya motor itu

dapat dijadikan motor elektrik a.t. dan berputar lebih laju.

Bab 8: Elektromagnet Chapter 8: Electromagnetism

Section C

(a) Most of our electrical energy comes from hydroelectric power stations and
thermal power stations. These power stations are connected by cables to
transmit electricity to users in industries, offices, schools and houses. This
system is called the national grid network.
Sebahagian besar tenaga elektrik yang digunakan datang daripada stesen
janakuasa elektrik hidro dan stesen janakuasa termal. Stesen janakuasa ini
disambung antara satu sama lain menggunakan kabel untuk menyalurkan
tenaga elektrik kepada industri, pejabat, sekolah dan rumah kediaman. Sistem
ini dikenali sebagai rangkaian grid nasional.

(i) What is the meaning of power
Apakah yang dimaksudkan dengan kuasa?

[1 mark]

(ii) Explain based on the transformations of energy and other physics concepthow
a hydroelectric power station generates electric energy.
Terangkan berdasarkan perubahan tenaga dan lain-lain konsep fizik
bagaimanakah sebuah stesen janakuasa elektrik hidro menjanakan tenaga
elektrik
[4 marks]

(b) Diagram 12 shows how a model of an electric transmission system can be set
up in a laboratory.The model consists of a power station that generates 12 V
of alternating current (a.c) that transmits the electrical energy to the users
using transmission wires and transformersP. Q and R.
Rajah 12 menunjukkan satu model sistem penghantaran tenaga elektrik yang
boleh dibina di dalam makmal. Model ini mengandungi satu stesen janakuasa
yang menjana 12 V arus ulang alik (a.u) yang menghantar tenaga elektrik
kepada pengguna menggunakan dawai penghantar dan transformer P. Q dan
R

Diagram 12
Rajah 12

Bab 8: Elektromagnet Chapter 8: Electromagnetism

You are required to set up a model as in Diagram12 using the information in
Table 12.
Anda dikehendaki untuk menyediakan model seperti dalam Rajah 12 dengan
menggunakan maklumat dalam Jadual12.

Number of turns Type of transformer core Materials of transmission wire
of the coil Jenis teras transformer Bahan dawai penghantar

bilangan lilitan Solid copper core Constantan
gegelung Teras kuprum pepejal Konstantan

1200 Laminated copper core Copper
1000 Teras kuprum berlamina Kuprum
500 Aluminium
400 Solid soft iron core Aluminium
160 Teras besi lembut
120 Laminated soft iron core Nichrome
Teras besi lembut Nikrom

berlamina

Table 12
Jadual 12

Using the information in Diagram 12 and Table 12, determine:
Menggunakan maklumat dalam Rajah 12 dan Jadual 12, tentukan:

(i) the number of turns in the primary coil and the secondary coil of transformers
P, Q and R and show your working.
bilangan lilitan dalam gegelung primer dan bilangan lilitan dalam gegelung
sekunder bagi transformer P, Q dan R dan tunjukkan kerja hitungan yang
anda lakukan.

(ii) the type of core you will use in all transformers and justify your choice.
jenis teras yang anda akan gunakan bagi semua transformer itu dan jelaskan
pilihan anda.

(iii) the material you will use for the transmission wire and justify your choice.
bahan yang anda akan gunakan untnk membina dawai penghantar dan
jelaskan pilihan anda.

[10 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(c) If the resistance of the transmission wires between transformers P and Q in
the model at Diagram 12 is 30Ω, calculate:
Jika rintangan dawai penghantar antara transformer P dan transformer Q
dalam model pada Rajah 12 ialah 30 Ω, hitungkan:

(i) the current that flows in the transmission wire,
arus yang mengalir dalam dawai penghantar itu.

(ii) the power loss due to the heating effect of the current in the transmission wire.
kuasa yang hilang disebabkan oleh kesan pemanasan arus dalam wayar
penghantar itu.
[5 marks]

Bab 8: Elektromagnet Chapter 8: Electromagnetism

ANSWER SCHEME 1
1(a)(i) 1
(ii) Move inwards 1
(b) Fleming’s Left Hand Rule 1
(c) Speed of the rod increased 4

Total

2. (a) A temporary magnet when there is a flow of electric current 1
(b) (i) 1

(ii) South / S 1
1
(iii) Attracted to iron nail (electromagnet) 15

(c) Magnetic lifting machine / circuit breaker / electric bell / electric
relay / ticker timer / magnetic levitated train / electronic card
/parking machine /tape recorder.

3(a) Aruhan elektromagnet ialah proses penghasilan daya gerak elektrik(d.g.e) aruhan
dalam satu konduktor akibat perubahan fluks magnet apabila wujud gerakan relatif
antara konduktor dan medan magnet.

(b) Utara

Bab 8: Elektromagnet Chapter 8: Electromagnetism
(c)

(d) Tambahkan bilangan lilitan gegelung solenoid//Gunakan magnet yang lebih kuat
(e) Hukum Lenz

4(a)(i) Increase the number of turns in the secondary coil. 1
(a)(ii) Decrease the number of turns in the primary coil. 1
(b) Can be magnetized and demagnetized easily 1
(c)(i) 36 = 24 x I 1
1
I = 1.5 A 1
(c)(ii) 36 = (240)Ip 17

Ip = 0.15A

Bab 8: Elektromagnet Chapter 8: Electromagnetism

5(a) 1 State the meaning of induced current correctly
(b) (i) The current that is induced by electromagnetic inductions when the
circuit is complete//The current that can be produced without any
(ii) electrical supply/source
(c) (i)
2 Label the polarity of each solenoid correctly
(ii) 1 X: N
(d) 2 Y: S

2 Label the direction of motion of each magnet correctly
Diagram 6.1 bar magnet towards the solenoid
Diagram 6.2 bar magnet away from the solenoid

2 State the type of force correctly
1 Repulsive
2 Attractive

1 Name the law correctly
Lenz’s Law

1 Correct suggestion
Increase the speed of bar magnet/increase the number of turns of the
solenoid/use a stronger magnet

6(a) Induced current 1
(b)(i) 1- Number of turns in Diagram 6.1 is greater. 1
1
2- Angle of deflection for galvanometer in diagram 6.1 is bigger. 1
(ii) 1- as the number of turns increases, the rate of change of magnetic flux
1
increases
2- hence, induced more current
(c) Faraday’s law
(d) 1- The current induced produces north pole on the left side// Lenz’s

Bab 8: Elektromagnet Chapter 8: Electromagnetism

Law

2- so as to oppose the oncoming magnet//the direction of the induced
current opposes the changes that producing it.

8(a)(i) Move upwards 1
(ii) Fleming’s Left-Hand Rule 1
(iii)
N
S

Direction of magnectic field of permanent magnet from north to 1
south 1
1
Direction of magnectic field of straigth wire, clockwise
1
Correct pattern

(iv) Use strong magnet/increasing the strength of the magnetic field //
increasing the current.

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(b)(i) Turning force / force increases 1
Speed of the motor increases 1

(ii) Increasing the number of turns in the coil 1
Increasing the strength of the permanent magnet 1

(iii) The coil not moving 1
The current always change direction. 1 12

SECTION B

9 ANSWER SCHEME

(a) A magnetic field is a region with a magnetic materials experiences magnetic 1
force. 1

Medan magnet ialah kawasan di mana bahan magnet mengalami daya
magnet.

(b) .. The number of turns od coil in Diagram 2 is greater than that of in
Diagram 1.

Bilangan lilitan gegelung pada Rajah 2 adalah lebih banyak
daripada biliangan lilitan gegelung pada Rajah 1.

.. The pattern of iron fillings in Diagram 2 is closer than that of in 1
Diagram 1

Corak serbuk besi pada Rajah 2 lebih rapat daripada corak serbuk
besi pada Rajah 1.

.. The deflection of the ammeter needle in Diagram 2 is more that that

Bab 8: Elektromagnet Chapter 8: Electromagnetism

in Diagram 1. 1

Pesongan jarum ammeter pada Rajah 2 lebih banyak daripada
pesongan jarum ammeter pada Rajah 1.

** The above answer can be presented in a table **

(c) (i).. The strength of the magnetic field is greater when the pattern of the 1
iron filling is closer.

Kekuatan medan magnet bertambah apabila bilangan gegelung
bertambah.

(ii).. The strength of the magnetic field increases as the number of turns of 1
the coil increases.

Kekuatan medan magnet bertambah apabila bilangan lilitan
gegelung bertambah.

(d) .. When the switch is on, current will flow in the circuit as shown 1
below.

Apabila suis dipasangkan, arus akan mengalir melalui litar seperti di
bawah.

1

Bab 8: Elektromagnet Chapter 8: Electromagnetism

.. The current flow creates magnetic field between the copper strips.

Arus yang mengalir menyebabkan medan magnet wujud antara jalur
kuprum.

.. The directions of the magnetic field and the current flowing in copper 1
strips are the same, the magnetic field between the strips become 1
stronger. This causes the strips to repel each other.

Arah medan magnet dan arus yang mengalir dalam jalur kuprum
adalah sama. Hal ini menyebabkan jalur-jalur kuprum itu menolak
antara satu sama lain.

(e) (i).. 1

.. As the a.c. current is supplied to the motor, the current coil produces
magnetic field around it.
Apabila arus a.u. dibekalkan kepada motor itu, arus gelung
menghasilkan medan magnet di sekelilingnya.

.. Reaction between the magnet and the magnetic field current results in 2
a resultant magnetic field. These two forces which are in opposite
direction produce a turning effect causing the coil to rotate.

Tindakan antara magnet dengan medan magnet arus menyebabkan
paduan medan magnet. Kedua-dua daya ini yang mempunyai arah
yang bertentangan menghasilkan kesan putaran yang menyebabkan
gelung itu berputar.

1

Bab 8: Elektromagnet Chapter 8: Electromagnetism

(ii)..

.. The slips rings are replaced with a commutator to change the current
from a.c. to d.c.
Gelang gelincir digantikan dengan komutator untuk mengubah arus
daripada a.u. ke a.t.

3

.. Add a rheostat and adjust the rheostat to reduce the resistance in the 1
circuit to let more current flow in the circuit in order to produce higher
magnetic fields.

Tambah rheostat dan laraskan rheostat untuk mengurangkan
rintangan dalam litar untuk membenarkan banyak arus mengalir
dalam litar untuk menghasilkan medan magnet yang lebih kuat.

.. Use armature with higher number of turns to increase the magnitude of
force acting on the side of the coil.

Guna angker dengan bilangan lilitan yang lebih banyak untuk
meningkatkan daya magnet yang bertindak ke atas gelung.

.. Use armature with larger area to increase the distance between the 1

Bab 8: Elektromagnet Chapter 8: Electromagnetism

lines of action of the force on the sides of the coil.

Guna angker dengan luas yang lebih besar untuk meningkatkan jarak
antara garis tindakan daya ke atas sisi gelung.

1

SECTION C

Section Mark Answer Note
12(a)(i) 1
Energy // Work // rate of energy // rate of work
(a)(ii) 1 t ime t ime

When water fall flow gravitational energy convert to

kinetic energy

1 The kinetic energy converted to mechanical energy
when fall to turbine//dynamo

1 Electromagnetic induction produce current

1 Mechanical energy convert to electrical energy

(b)(i) Transformer P:

1 NP  12 ,
NQ 24

NP = 500 ,NS= 1000
1

Transformer Q:

1 NP  24 ,
NQ 8

1 NP = 1200 ,NS= 400

Transformer R:
1 NP  8 ,

NQ 6

Bab 8: Elektromagnet Chapter 8: Electromagnetism

1 NP = 160 ,NS= 120

(b)(ii) 1 Laminated soft iron core
(b)(iii) 1 Easily magnitised / demagnitised // Reduced
(c)(i)
(c)(ii) hystherisis loss

Total 1 Copper // aluminium
1 Small resistance // less loss of power in cable

1 Current = 30
24

1 = 0.8 A First mark : correct
1 P = I2 R formula

1 = (0.8)2(30)
1 = 19.2 W

20

Bab 9: Elektronik Chapter 9: Electronics

1. Rajah 1 menunjukkan satu simbol peranti elektronik
Diagram 1 shows an electronic device symbol.

Rajah 1

(a) Underline the correct answer in the bracket to complete the sentence below
Garis jawapan yang betul di dalam kurungan untuk melengkapkan ayat di bawah.
Device X is a symbol for (diode, transistor)
Peranti X adalah symbol untuk (diod, transistor)
(1 markah)

(b) (i) Label the direction of current flow in the circuit
Labelkan arah pengaliran arus yang betul dalam litar.

(1 markah)

(ii) State why the bulb in Figure 1 does not light up.
Nyatakan mengapa mentol di dalam Rajah 1 tidak menyala.

______________________________________________________________________
( 1 markah)

(c) What is the function of electronic devices in Diagram 1?
Apakah fungsi peranti elektronik di dalam Rajah 1?

_____________________________________________________________________
(1 markah)

1

Bab 9: Elektronik Chapter 9: Electronics

2 Diagram 4.1 and Diagram 4.2 show two circuits which consist of identical batteries, bulbs
and diodes.
Rajah 4.1 dan Rajah 4.2 menunjukkan dua litar yang mengandungi bateri, mentol dan diod
yang serupa.

Diagram 4.1 Rajah 4.1 Diagram 4.2 Rajah 4.2

(a) Name the two types of semiconductors used in a diode.
Namakan dua jenis semikonduktor yang digunakan dalam satu diod.

1._______________________________________________________________________

2. ______________________________________________________________________
[2 markah ]

(b) Based on your observation in Diagram 4.1 and Diagram 4.2, state the difference in
Berdasarkan pemerhatian anda dalam Rajah 4.1 dan Rajah 4.2, nyatakan perbezaan
dalam
(i) the connection of the diodes,
penyambungan diod,

_____________________________________________________________________
[1 markah]

(ii) the lighting of the bulbs,
penyalaan mentol,

_____________________________________________________________________
[1 markah]

(iii) the current flowed.
pengaliran arus.

_____________________________________________________________________
[1 markah]

2

Bab 9: Elektronik Chapter 9: Electronics

3 Diagram 4.1 shows the use of a transistor in a circuit.
Rajah 4.1 menunjukkan kegunaan transistor dalam suatu litar.

R1 = 1500 Ω IB Bulb
R2 V2 IC
6V
IE

DIAGRAM 4.1 / RAJAH 4.1

(a) Name the type of transistor used.
Namakan jenis transistor yang digunakan.

________________________________________________________________________
[1 markah]

(b) The transistor is switched on when the base voltage V2 ≥ 2 V.
Transistor itu dihidupkan apabila voltan tapak V2 ≥ 2 V.

(i) Write an equation to show the relationship between IB, IC and IE.
Tuliskan satu persamaan untuk menunjukkan hubungan antara IB, IC dan IE.

________________________________________________________________________
[1 markah]

(ii) Calculate the minimum value of R2 when the transistor is switched on.
Hitungkan nilai minimum R2 apabila transistor itu dihidupkan.

[2 markah]
3

Bab 9: Elektronik Chapter 9: Electronics

(c) The resistor R2 is then replaced with a light dependent resistor which has a high
resistance when it is dark.
Perintang R2 kemudian digantikan dengan perintang peka cahaya yang mempunyai
rintangan tinggi apabila keadaan sekitar gelap.

(i) Explain whether the bulb will light up during the day.
Jelaskan sama ada mentol itu menyala pada waktu siang.

______________________________________________________________________

______________________________________________________________________

[2 marks]
4. Diagram 1 shows the structure of a simple cathode ray oscilloscope. Electrons are produced

from the filament, F in the process of thermionic emission.
Rajah 1 menunjukkan struktur bagi osiloskop sinar katod ringkas. Elektron dihasilkan
daripada filamen, F dalam proses pancaran termion.

Diagram 1 Rajah 1

(a) Explain what is meant by the process of thermionic emission.
Terangkan apa yang dimaksudkan dengan proses pancaran termion.
________________________________________________________________________
[1 markah]

(b) What is the function of anode, A in the cathode ray tube?
Apakah fungsi anod, A dalam tiub sinar katod?
________________________________________________________________________
[1 markah]

4

Bab 9: Elektronik Chapter 9: Electronics

(c) Why the space inside the cathode ray tube must be vacuum?
Mengapakah ruang dalam tiub sinar katod mesti divakumkan?

________________________________________________________________________
[1 markah]

(d) What happen to the electrons when hit the screen of the cathode ray tube?
Apakah yang berlaku kepada elektron apabila menghentam skrin bagi tiub sinar katod?

________________________________________________________________________
[1 markah]

(e) Explain what will happen if the current through the filament is increased.
Terangkan apa yang akan berlaku jika arus melalui filamen ditambahkan.

________________________________________________________________________

________________________________________________________________________
[2 markah]

(f) What will happen to the electron ray in Diagram 1 if switch S is turned on?
Apakah yang akan berlaku kepada sinar elektron dalam Rajah 1 jika suis S dihidupkan?

________________________________________________________________________
[1 markah]

5 Table 3 shows a truth table for a combination of logic gates.
Jadual 3 menunjukkan jadual kebenaran bagi satu kombinasi get logik.

Input Output
KL M
00 0
01 0
10 1
11 0

Table 3
Jadual 3

5

Bab 9: Elektronik Chapter 9: Electronics

(a) Using a logic gate NOT and a logic gate AND, construct a combination of logic gates
which produces the truth table as shown on Table 3.
Dengan menggunakan satu get logik TAK dan get logik DAN, binakan satu kombinasi get
logik yang menghasilkan jadual kebenaran seperti dalam Jadual 3.

[2 markah]

(b) Diagram 2 shows a circuit consists of four NAND gates.
Rajah 2 menunjukkan satu litar yang mengandungi empat get TAK-DAN.

Diagram 2
Rajah 2

(i) Based on the combination of logic gates in Diagram 2, complete the truth table in
Table 4.
Berdasarkan kombinasi get logik dalam Rajah 2, lengkapkan jadual kebenaran
dalam Jadual 4.

Input Output

A B CDE F

00

01

10

11

Table 4
Jadual 4

[4 markah]

6

Bab 9: Elektronik Chapter 9: Electronics

(ii) Draw a combination of logic gate that can replace a NAND gate.
Lukiskan satu kombinasi get logik yang boleh menggantikan get TAK-DAN.

[2 markah]

6 Diagram 6.1 and Diagram 6.2 show the screen of a cathode ray oscilloscope that displays a
waveform when the input is connected to two different sources, K and L. The time-base is
set to 10 ms/div and the Y-gain is 0.1 V/ div.
Rajah 5.1 dan Rajah 5.2 menunjukkan skrin osiloskop sinar katod yang memaparkan satu
bentuk gelombang apabila input disambung kepada dua sumber yang berbeza, K dan L.
Dasar-masa ditetapkan pada 10 ms/div dan gandaan-y ialah 0.1 V/div.

Diagram 6.1 Diagram 6.2
Rajah 6.1 Rajah 6.2

(a) (i) What is the peak voltage of source K?
Berapakah voltan puncak bagi sumber K?

_____________________________________________________________________
[1 markah

(ii) What is the period of the source K?
Berapakah tempoh bagi sumber K?

[2 markah]
7

Bab 9: Elektronik Chapter 9: Electronics

(iii) Determine the frequency of the source K.
Tentukan frekuensi bagi sumber K.

[2 markah]

(iv)What is the voltage of source L?
Berapakah voltan bagi sumber L?

[2 markah]

(b) State one difference between sources K and L.
Nyatakan satu perbezaan antara sumber K dan sumber L.

______________________________________________________________________
[1 markah]

7 When a robber opens the door of a goldsmith shop which has been fixed with an alarm
system, the alarm will activate continuously even though the door is closed again. The
alarm system has a flip-flop circuit which consists of two NAND gates.
Apabila seorang perompak membuka pintu suatu kedai tukang emas yang dipasang
dengan satu sistem penggera, penggera akan diaktifkan berterusan walaupun pintu ditutup
semula. Sistem penggera mempunyai litar flip-flop yang mengandungi dua get TAK-DAN.

(a) (i) Draw the symbol for NAND gate.
Lukiskan simbol bagi get TAK-DAN.

[1 markah]
8

Bab 9: Elektronik Chapter 9: Electronics

(ii) Complete the truth table in Table 1 for NAND gate.
Lengkapkan jadual kebenaran dalam Jadual 1 bagi get TAK-DAN.

Input Output
00
01
10
11

Table 1
Jadual 1

[2 markah]

(b) Draw the flip-flop circuit diagram which uses two NAND gates. Label both input and
output.
Lukiskan rajah litar flip-flop yang mengguna dua get TAK-DAN. Labelkan kedua-dua
input dan output.

[4 markah]
(c) Complete the truth table in Table 2 for the flip-flop circuit of an alarm system.

Lengkapkan jadual kebenaran dalam Jadual 2 bagi litar flip-flop untuk satu sistem
penggera.

Input Output Alarm condition:
Activated/Not
activated

Keadaan penggera:
Aktif/Tidak aktif

1111 Not activated
Tidak aktif

10

11

01

Table 2
Jadual 2

[3 markah]

9

Bab 9: Elektronik Chapter 9: Electronics

8. Diagram 8 shows an electronic circuit consists of a transistor which acts as an automatic
switch.
Rajah 8 menunjukkan satu litar elektronik yang mengandungi satu transistor yang bertindak
sebagai suis automatik.

Diagram 8
Rajah 8

(a) (i) Name the type of transistor used in the circuit.
Namakan jenis transistor yang digunakan dalam litar.

_____________________________________________________________________
[1 markah]

(ii) State the function of resistors R1 and R2.
Nyatakan fungsi perintang R1 dan R2.

_____________________________________________________________________
[1 markah]

(iii) R2 is known as light dependent resistor. Explain the characteristics of R2.
R2 dikenali sebagai perintang peka cahaya. Terangkan ciri-ciri bagi R2.

_____________________________________________________________________

_____________________________________________________________________
[2 markah]

(b) (i) In your opinion, the relay will work in the day time or at night ?
Pada pendapat anda, geganti akan berfungsi pada waktu siang atau waktu malam?

_____________________________________________________________________
[1 markah]

10

Bab 9: Elektronik Chapter 9: Electronics

(ii) Give reasons for your answer.
Berikan sebab bagi jawapan anda.
____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
[3 markah]

(iii) State one use of the electronic circuit in Diagram 3.
Nyatakan satu kegunaan litar elektronik dalam Rajah 3.

_____________________________________________________________________
[1 markah]

(c) The electronic circuit in Diagram 3 also can be used as a fire alarm device. How do you
modify the circuit so that the circuit can be used as a fire alarm device?
Litar elektronik dalam Rajah 3 juga boleh digunakan sebagai alat penggera kebakaran.
Bagaimanakah anda mengubahsuaikan litar itu supaya litar tersebut boleh digunakan
sebagai alat penggera kebakaran?

________________________________________________________________________

_______________________________________________________________________
[2 markah]

9. (a) Diagram 9.1 and Diagram 9.2 show two electrical circuits consisting of semiconductor
diodes, bulbs and dry cells.
Rajah 9.1 dan Rajah 9.2 menunjukkan dua litar elektrik yang mengandungi diod
semikonduktor, mentol dan sel kering.

Diagram 9.1 Diagram 9.2
Rajah 9.1 Rajah 9.2

What is meant by a semiconductor?
Apakah yang dimaksudkan dengan semikonduktor?

[1 markah]

11

Bab 9: Elektronik Chapter 9: Electronics

(b) Based on your observation in Diagram 9.1 and Diagram 9.2, state the difference in the
connection of the diodes, lighting of the bulbs and the current to deduce a physics
concept.
Berdasarkan pemerhatian anda dalam Rajah 9.1 dan Rajah 9.2, nyatakan perbezaan
dalam penyambungan diod, penyalaan mentol dan arus untuk menyimpulkan satu konsep
fizik.
[5 markah]

(c) Diagram 9.3 shows a full-wave rectification formed by 4 diodes.
Rajah 9.3 menunjukkan satu rektifikasi penuh gelombang yang terbentuk daripada 4 diod.

Diagram 9.3
Rajah 9.3

(i) Draw the output waveform of the full wave rectification.
Lukiskan bentuk gelombang output bagi rektifikasi penuh gelombang.

[1 markah]

(ii) A capacitor is connected across the output to smooth the current. Draw the output
waveform and explain how the capacitor smoothen the current.
Satu kapasitor disambung merentasi output untuk meratakan arus. Lukiskan bentuk
gelombang output dan terangkan bagaimana kapasitor meratakan arus.
[3 markah]

12

Bab 9: Elektronik Chapter 9: Electronics

(c) Diagram 9.4 shows an electronic circuit which consists of a transistor that is used as
automatic switch.
Rajah 9.4 menunjukkan satu litar elektronik yang mengandungi satu transistor yang
digunakan sebagai suis automatik.

Diagram 9.4
Rajah 9.4

The transistor lights up the bulb when light strikes onto light dependent resistor (LDR).
A house owner wants an electric siren labelled 240 V, 500 W to activate automatically if
the house is hot due to fire.
Transistor menyalakan mentol apabila cahaya menghentam ke atas perintang peka
cahaya (PPC). Seorang tuan rumah mahu siren elektrik yang berlabel 240 V, 500 W aktif
secara automatik jika rumahnya dipanaskan oleh api.

Suggest modifications that is required by the circuit in Diagram 6.4, so that the siren can
be switched on automatically when the room in the house is hot.
Draw the modified circuit. Explanation of the modifications have to include the following
aspects:

• the electrical components that are needed to replace the components in the circuit.
• the positions of the electrical components in the new circuit.

Cadangkan pengubahsuaian yang diperlukan oleh litar dalam Rajah 6.4 supaya siren itu
boleh dihidupkan secara automatik apabila bilik dalam rumah adalah panas.
Lukiskan litar yang diubahsuaikan. Penerangan bagi pengubahsuaian hendaklah meliputi
aspek-aspek berikut:

• komponen-komponen elektrik yang diperlukan untuk mengganti komponen-komponen
dalam litar.

• kedudukan komponen-komponen elektrik dalam litar baru.
[10 markah]

13