jwpn 3.3

Bateri merupakan sumber yang
membekalkan tenaga elektrik untuk
menggerakkan cas mengelilngi litar.
Battery is a source of electrical
energy which move the charges
around the circuit.

Bateri menukarkan tenaga kimia yang
tersimpan (elektrolit) kepada tenaga
elektrik.
Battery convert chemical energy
stored (electrolyte) to electrical
energy.

Tenaga yang dibekalkan ini
memindahkan 1 C cas dalam litar.
The energy supplied move 1 C of
charge in the circuit.

Setiap 1 C cas yang mengalir melalui
bateri akan memperoleh tenaga
keupayaan elektrik untuk bergerak
dalam litar.
Each 1 C of charge that flow through
the battery will receive electric
potential energy to move in the circuit

Bateri yang membekalkan tenaga Oleh itu, kerja dilakukan oleh bateri
elektrik ialah suatu sumber daya untuk menggerakkan cas mengelilingi
gerak elektrik. litar.
Battery that provides electrical energy Therefore, work is done by the battery
is a source of electromotive force. in driving the charges around a
complete circuit.



Mentol menyala dengan kecerahan malap.
Bulb lights up with low brightness.

Mentol menyala dengan lebih cerah
Bulb lights up brighter

Tenaga kimia ke tenaga elektrik ke tenaga cahaya + haba
Chemical energy to electrical energy to light + heat energy.

Semakin banyak tenaga, semakin cerah mentol
The more the energy, the brighter the bulb.

9V

D.g.e ialah jumlah kerja yang dilakukan oleh
suatu sumber untuk menggerakkan 1 C cas
dala satu litar yang lengkap.
E.m.f is total work done by a source in
driving 1 C of charge around a complete
circuit.

d.g.e ialah jumlah tenaga yang dibekalkan
untuk menggerakkan 1 C cas dalam satu
litar yang lengkap.
e.m.f is total energy supplied to drive 1 C of
charge around a complete circuit.

SI unit for e.m.f is volt (V) = J/C @ J C-1
Unit SI bagi d.g.e ialah volt (V) = J/C @ J C-1

1.5 J tenaga diperlukan untuk
menggerakkan 1 C cas melalui satu litar
yang lengkap.
1.5 J of energy is needed to move 1 C of
charge around a complete circuit.

• Label pada bateri
menunjukkan d.g.e bateri.

• The voltage label on a battery
or cell indicates its e.m.f

MOZAC

MOZAC

Litar terbuka / Open Circuit

Bacaan No
Ammeter = 0 3.0 V
Ammeter
reading = 0 3.0 V

Bacaan
Voltmeter = 3.0 V
Voltmeter
reading = 3.0 V

Litar tertutup / Closed Circuit

Bacaan Yes
Ammeter = 0.2 A (0.2 A)
Ammeter
reading = 0.2 A 2.7 V

Bacaan V litar tertutup
Voltmeter = 2.7 V lebih rendah
Voltmeter V in closed
reading = 2.7 V circuit is lower

3.0 – 2.7
= 0.3 V

Litar terbuka / Open Circuit Voltmeter reading,
e.m.f.
• Tiada arus mengalir
• No current flows through the circuit R
• Bacaan voltmeter = 3.0 V No current flow
• The voltmeter reading = 3.0 V.

• D.g.e = bacaan voltmeter yang
disambungkan merentasi terminal
bateri.

• The e.m.f. = the reading of the
voltmeter which is connected directly
across the terminals of the cells.

• D.g.e // e.m.f. = 3.0 V

MOZAC

Litar tertutup / Closed Circuit

Arus mengalir dalam litar.
Current flows through the circuit

Bacaan voltmeter berkurang jika
lampu disambung sesiri dengan bateri
The reading of the voltmeter will drop
if a lamp is connected in series to the
cell.

Jika bacaan voltmeter ialah 2.4 V, beza
keupayaan merentasi lampu = 2.4 V
If the voltmeter reading is 2.4 V, then the
potential difference across the lamp = 2.4 V

Tidak menyala
menyala 0.3 A

0A

3.0 V 2.4 V

3.0 V
2.4 V

Suis S dibuka, tiada bacaan.
Suis S ditutup, ada bacaan.
Circuit open, no reading.
Circuit close, there is a reading

Bacaan voltmeter semasa suis S ditutup lebih rendah.
The voltmeter readings when switch S is closed is lower.

3.0 V 2.7 V

Dge = 3.0 V Emf = 3.0 V

3 J tenaga dibekalkan untuk gerakkan 1 C cas dari bateri
3 J of energy is supplied to move 1 C of charge from a battery.

Tenaga elektrik ke tenaga cahaya
+ haba
Electrical energy to light + heat
energy

Beza keupayaan = 2.4 V 2.4 J tenaga elektrik dibebaskan ke
Potential difference = 2.4 V mentol bagi setiap 1 C cas.
2.4 J of electrical energy emitted to
the bulb for 1 C of charge.

Bacaan voltmeter apabila suis dibuka Bacaan ini merupakan tenaga
ialah d.g.e bateri. maksimum seunit cas yang boleh
The reading of the voltmeter when dibekalkan oleh sel kering.
the circuit is open = e.m.f of the This is the maximum energy per unit
battery. charge which can be supplied by the
cell
D.g.e bagi satu sel kering diukur
dalam litar terbuka bila arus tidak
mengalir
E.m.f for a dry cell is measured in an
open circuit when current does not
flow.

Dge = 3.0 V Emf = 3.0 V

Bacaan voltmeter apabila suis ditutup
ialah beza keupayaan antara terminal sel.
When the circuit is closed, the reading of
the voltmeter is the potential difference
between the terminals of the cell

Beza keupayaan diukur dalam suatu Bacaan ini ialah tenaga yang
litar tertutup apabila arus mengalir. dilesapkan seunit cas oleh
The potential difference is measured perintang, R.
in a closed circuit in which the current This is the energy dissipated
flows. per unit charge by the
resistor, R

Perbezaan antara d.g.e dan beza keupayaan
Difference between e.m.f and potential difference

Daya Gerak Elektrik, E Beza keupayaan, V

Electromotive Force, E Potential Difference, V

Tenaga elektrik dibekalkan Tenaga elektrik yang dibebaskan

kepada 1 C cas untuk mengalir ke bentuk tenaga lain apabila 1 C

dalam litar lengkap. cas melalui satu komponen

The electrical energy given to 1 dalam litar tertutup.

C of charge flowing a complete The electrical energy that is

circuit. transformed to other forms of

energy when 1 C of charge passes

through a component in a

closed circuit.

Daya Gerak Elektrik, E Beza keupayaan, V
Electromotive Force, E Potential Difference, V
Digunakan pada sumber tenaga Used in reference to electrical
elektrik seperti sel dan bateri component in a circuit.
Used in reference to source of
electrical energy ie battery Bacaan voltmeter dalam litar
Bacaan voltmeter dalam litar tertutup (suis ditutup)
terbuka (suis dibuka)
The voltmeter reading in an open The voltmeter reading in a closed
circuit (when switch is opened) circuit (when switch is closed)
Unit JC-1 @ Volts,V
Unit JC-1 @ Volts,V

MOZAC

D.g.e ialah jumlah kerja yang Beza keupayaan ialah kerja yang
dilakukan oleh suatu sumber untuk dilakukan oleh suatu sumber untuk
menggerakkan 1 C cas dalam satu litar menggerakkan 1 C cas antara dua titik

yang lengkap. dalam litar tertutup.
E.m.f is total work done by a source in Potential difference is the work done
by a source in driving 1 C of charge
driving 1 C of charge around a between two points in a closed circuit
complete circuit.

Terdapat rintangan dalam disebabkan • Kerja perlu dilakukan untuk
elektrolit dalam bateri menggerakkan cas mengatasi rintangan
There is an internal resistance due to dalam
electrolyte in the battery..
• Work is needed to drive a charge against
RinRtianntagnagann dyiasenbgabmkaneneleekntrtoalint dgalgaemrbaaktearni cas the internal resistance.
dRiesseistbaancbekdauentoeelelekcttrroolyltietindtahleabmatebrya;.teri
• Ini menyebabkan terdapat kehilangan
Resistance against the moving charge beza keupayaan merentasi bateri semasa
due to electrolyte in the battery cas mengalir melaluinya dan hilang
tenaga sebagai haba dalam bateri.

• This causes a drop in potential difference
across the cell as the charge flows
through it and loss of heat energy in the
cell.

Terangkan persamaan menghubungkan E, V, I dan r
Explain equation relates, E, V, I, and r

Arus mengalir dalam sel sama dengan arus yang mengalir dalam
litar luar.
The current in the cell is the same as the current in the external
circuit.

Kerja untuk menggerakkan 1 C Kerja untuk menggerakkan 1 C Kerja untuk menggerakkan 1 C

cas dalam litar lengkap = +cas dalam litar luar cas dalam litar dalam. Work done
Work done in driving 1 C of Work done in driving 1 C of charge in driving 1 C charge in the

charge around a complete circuit in the external circuit internal circuit.

d.g.e, E = +Beza keupayaan, V Kehilangan beza keupayaan disebabkan rintangan dalam
e.m.f, E Potential Difference, V Drop in potential difference due to internal resistance.

E = V + Ir E = d.g.e V = beza keupayaan R = perintang luar r = rintangan dalam I = arus
E = IR + Ir E = e.m.f V = potential difference R = externar resistance r = internal resistance I = current
@ E = I(R + r)

E = V + Ir
E = IR + Ir = I [R + r]





Semakin bertambah arus, semakin berkurang Rintangan dalam / internal resistance
beza keupayaan
The higher the current, the lower the voltage Daya gerak elektrik
electromotive force, E

V = - (I)r + E

y = mx + c

3.0 V

2.4 – 3.0 V
0.6 – 0 A

1.0 VA-1 @ 1.0 Ω

Graf yang diplotkan
merupakan satu garis lurus:

The graf is a straight line:
V = -Ir + E (E = V + Ir)

Jika garis lurus itu Rintangan dalam, r, boleh ditentukan
diekstrapolasikan sehingga daripada kecerunan graf
memotong paksi-Y, iaitu V:
If the straight line is extrapolated The internal resistance, r can be determined
until it cuts the vertical axis V: from the gradient of the graph.

I = 0 and V = E

Ini menunjukkan beza keupayaan merentasi terminal sel ialah
daya gerak elektrik apabila tiada arus yang mengalir dalam litar.
This shows that the potential difference across the terminals of

the cell is the electromotive force when no current flows.

• Determine:

• the e.m.f of the cell

• E = 1.5 V
• the internal resistance of the cell
• r = - gradient = (1.5 – 0.9)/0.6 = 1.0 Ω

MOZAC

E = I (R + r) = 2 = I (4 + 1) = 5I
I = 2/5 = 0.4 A

V = IR = 0.4 x 4 = 1.6 V

(a) E = 6.0 V
(b) V = IR

I = V/R = 4.8 / 8.0 = 0.6 A

(c) Ir = E – V = 6.0 – 4.8 = 1.2
r = 1.2/0.6 = 2.0 Ω

(a) E = 1.5 V

(b) internal resistance
Ir = E – V = 1.5 – 1.35
r = 0.15/0.3 = 0.5 Ω

(c) resistance of R
V = IR = 0.3 R = 1.35
R = 1.35/0.3 = 4.5 Ω

• Which of the two electrical quantities are measured
in volts?

A. Current and e.m.f, E
B. Current and resistance
C. e.m.f, E and potential difference
D. Potential difference and resistance

MOZAC

MOZAC

MOZAC

• One coulomb of charge emerging from the battery
and entering a circuit has a maximum of 1.5 joules of
energy. What electrical quantity is being described?

A. Current
B. Power
C. Electromotive force
D. Potential difference

MOZAC

MOZAC

MOZAC

Why the potential difference across the cell
decreases when the current increases?

• When the switch is opened, the voltmeter = _z_e_r_o__ ,
,current, I = _e_._m__.f_, E

• When the switch is closed, __cu__r_re_n__t flows through the
circuit and there is a drop in _p_o_t_e_n_t_i_a_l_ d_i_f_fe__re__n_cedue to
the _in__te_r_n__a_l ___ resistance, r in the cell (V = Ir)

• The readings of the voltmeter decreases as V =

___E_-_I_r______
• The bigger the current, the __l_a_r_g_e_r____ the drop in

potential difference (Ir) and the __lo_w__e_r_____ the reading

of the voltmeter, V.

MOZAC

• Total e.m.f = 2 x 1.5 = 3.0 V • Total e.m.f = 1.5 V
• Effective internal resistance, • Effective internal resistance,

r = 2 x 0.5 = 1.0 Ω r = 0.5/2 = 0.25 Ω

MOZAC

• Can a 12 V lead acid accumulator be replaced with
12 V dry cells to start a car?

MOZAC

• No.
• Because a 12 V lead acid accumulator has an

internal resistance of 0.01 Ω.
• A dry cell of e.m.f 1.5 V has an internal resistance

of 0.5 Ω.
• When 8 dry cell are arranged in series to make up

12 V, the total internal resistance will be 4 Ω.
• Thus the current produced will not be enough to

start the car which needs a high surge current of a
least 100 A to operate.

MOZAC

What is the difference between e.m.f, E, potential
difference across the cells and potential difference
across the external resistor?

MOZAC

• What happens to the potential difference across the
cells, V as current increases?

• Potential difference across the cells decreases as
current increases

MOZAC