For each of the questions, there are four possible

choices. Choose the one you consider correct andrecord your choice.

U l. What is electrical current?

A rate ofchange ofvoltageB rate ofchange ofresistanceC rate offlow ofchargeD rate of flow of power

t\,g 6V5. How much charge

flows through theresistor in 4 s?

A 3Cc t2c

3

())

t\,0

t\,0

2. What is meant by 5 A?

A 5 C of charge flows through a point in Isecond.

B 5 V ofelectricity across I Cl ofresistance.C 5 V of electricity causing lC of charge to

flow.D 5 C of charge flowing through a point.

()

3. Which of the following is true about point P?

6V3A

2A

2R

A Current is flowing in direction 4.

B Electron is flowing in direction 4.

C Electron is flowing in either direction 1 ordirection 3.

D Electron is flowing in direction 2. ( )

4. Which is a unit of current?

AQV BVRC Cs-' D CV

IVg 6. If 50 C of charge flows through a point inan electric circuit in 10 s, what is the currentpassing through that point?

A O.2A B 5,Ac60A Ds00A ( )

U 7 . Acell containing 1200 C of charge is connected

to a circuit. What is the time taken to discharge

the cell given that the current of the circuit is

6A?

A 0.005 h B 200 h

C 200s D 7200s ( )

U 8. There is 100 C of charge stored in a cell. Giventhat 5OVo of the charge flows out of the cell inl0 s, what is the average rate of flow of charge

out of the cell?

A O.IA B O.5Ac sA D tOA ( )

\\,0 q. Electromotive force is defined as

A the work done by an appliance in drivingelectrons round a circuit.

B the work done by a source in driving a unitcharge round a circuit.

C the work done to drive a unit charge througha component.

D the product ofcurrent and resistance.

()

2

Mg

93 Unit 16 Cunent of Electricity and D.C. Circuits

Gurrent of Electricity andand

Magnetism

B 6CD I8C

Theme 5

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Nu, A resistance wire AB is connected in a circuitas shown. What happens to the brightness of the

lamps as the jockey slides along the resistance

wire from point A to point B?

A B

5C) 5c)

10c,

LampP LampQ

A Lamp P gets brighter while lamp Q gets

dimmer.

B Lamp Q gets brighter while lamp P gets

dimmer.

C There is no change in the brightness of lamp

P and lamp Q.D Both lamp P and lamp Q do not light up.

()

Extension Questions

WOr. *nu, is the effective resistance of the nine

resistors?

2012

A 5clC 15Q

B 10c)D 2OQ (

20f2

10c)

10Q l0o

10c)

U ur. *nu, is the value of current 1,?

t2Y

A IAC4A

t2v

A 1AC 4A

lo

2Q

2A

20

()

()

3

Il

U *. *u, is the value of current 1,?

t2v

l.0A2.0 A

4Q

B3AD 12A

4A

B3AD6A

4Q

20B 1.5AD 3.OA

4

Il

Vur. *nu, is the value of current /,?

It

AC )

l0l Unit 16 Current of Electricity and D.C. Circuits

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U

Vu,

Vut

66. Which of the following produce(s) directcurrent?

I

time

e.m.f.

2

4J

timetime

A resistor can be added to the circuit below tomake the current 1= 3A'. Which is it?

t2v

A 4 onlyB 3and4onlyC 2,3 and 4 onlyD 1,2 and 3 only

A 2QC 6cl

A2AC lOQ

()

)

A resistor can be added to the circuit below tomake the current 1= 3A. Which is it?

t2v

B 4c)D 8C)

B 6C)D 12Q (

69. The circuit diagram shows four identicalresistors connected in a series with a battery.

What are the possible readings on voltmeters

V, and Vr?

2A 4A

U

102 Unit 16 Current of Electricity and D.C. Circuits

I

vr

A IVB2YC 3VD 4V

12A

A 3AC6A

Y2

3V8V6V6V

B4AD8A ()

)

IMg 70. A student wants to know the resistance of a

conductor when a current 1 = 0.50 A flowsthrough it. How can he obtain the result?

A By calculating the gradient of a V-I graph.

B By calculating the gradient of a I-V graph.

C By calculating the gradient of a V-I graph

at 1= 0.50 A.D Obtain the corresponding p.d. V across the

conductor when 1= 0.50 A. Then calculate

resistance uring ;}. ( )- 0.50

U 7l . Which of the following statements is correct?

I2

=1:and Ir=lr+lr.is smaller than 1, but bigger than I r.is greater than 1, but smaller than /,.is greater than Irbut smaller than 1r.

()

U rr. *nu, is the value of current /?

ll

AI,B1,CI,D1,

lo

2A

6O

3C,

I

(

I

)

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V,, In the flgure below, AB is a 2 m long resistance

wire. When AC = 1.6 m, the galvanometer

indicates a zero reading.

1.6 m+------------------)

C

What is the resistance of R?

46C, B IzC)c 24d, D 30O ()

U 74.Three resistors, each of resistance 6 C), are

arranged to give a 9 C2 combination across PQ.

Which of the following is the arrangement?

A

P

BP

C

P

D

P

o

o

a)

U

U

75. In an experiment, four resistance wires made

from the same material are connected in turn

between the terminals P and Q in the circuitshown. The length and diameter of the wires

are different.

PQ

Which wire will give the smallest reading on

the ammeter?

Length Diameter

A 0.5 m 0.5 mm

B 0.5 m 0.05 mm

C 5.0 m 0.5 mm

D 5.0m 0.05mm ( )

76. What happens to the brightness of the lamp

when the switch is closed?

A It becomes dimmer.

becomes brighter.goes off.remains the same.

BItCItDIt

\\,s

A 0.17Ac 0.67 A

B 0.33 AD 1.00,4

(

()

77. Six 6 C) resistors are connected to a 6 V cell ofnegligible internal resistance as shown below.

What is the current that flows through pointP?

P

6c) 6O

\o

6C) 6Q

103 Unit 16 Current of Electricity and D.C. Circuits

6C,R

(

6O

6Q

6O

6O 6c) 6O

6C, 6C,

6C,

6C)

6c, 6C2

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6O

€d

€

6o

V,,

\\,s

MCI

Five 6 O resistors are connected to a 6 V cell ofnegligible internal resistance as shown below.

What is the current that flows through pointP?

P

A 0.20 Ac 0.50 A ()

79. In the circuit shown below, the ammeter reads

0.50Awhen S, is closed and S, is opened. Whatwould the ammeter reading be if both S, and S,are closed?

6V

B 0.25 AD 1.25 A

B 0.75 AD 3.00A

sr

A 0.67 Ac 1.33 A (

80. In the figure below, lamp P has twice the

resistance of lamp Q.The relationship between

the current 1 and current 1 ispq

PIP

B 2l =lpqD I =41pq

A 4I =lpqCI=21

Pq )

IVCI

i\,g

81. Which of the following graphs shows therelationship between the resistance R of a wire,and its cross-sectional area A?

R R/Q B

Al mmz A/ mmz

OA

RIA C RI D

Al mm2 Almmz

()

82. Which of the following statements is correctfor the circuit shown below?

A The bulb becomes brighter when therheostat is adjusted to a higher resistance

because as the resistance increases, thepotential difference increases.

B The bulb becomes dimmer when the rheostat

is adjusted to a higher resistance because

as the resistance decreases, the potential

difference decreases.

C The brightness of the bulb cannot be

adjusted because the potential differenceacross the bulb is constant.

D The brightness of the bulb cannot be

adjusted because its resistance is constant.()

104 Unit 16 Current of Electricity and D.C. Circuits

)

6C)

3Q

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83. Acircuit is connected as shown in the diagram.

Given that the three resistors are identical,which of the following statements are true?

I A, has the highest reading.

2 Ar, A, and A, have the same reading.

3 Reading of A, is greater than Au.

A land2onlyC 2and3only

B land3onlyD 1,2 and3 (

84. Resistors R, and R, are connected in a circuitas shown below. When switch S is opened, the

ammeter reads 1.5 A and the voltmeter reads

9 V. When switch S is closed, the ammeter

reads 3.0 A and the voltmeter reads 6 V.

S

What are the resistances of R, and Rr?

R,/Q Rr/C2

A3 6

B6 3

c4 8

D8 4 ( )

\V0r85. In the circuit below, the three lamps are

identical. When switch S is closed,

P

R

Vru

S

A lamp P becomes dimmer.

B lamp P is as bright as lamp Q.C lamp P is not as bright as lamp R.

D lamp Premains as bright as when switch S

is opened. ( )

A heater is connected to the 12 V battery as

shown in the diagram.

t2v

1A

heater

The fan with a resistance of R has a p.d. of6 V across it and a current of I A through it.The bulb has a current of 2 A flowing thoughit. Which of the following is true?

A The voltage across the bulb is 6 V and its

resistance is 2R.

B The voltage across the bulb is 6 V and its

resistance is 1n.2

C The voltage across the bulb is 3 V and its

resistance is 2R.

D The voltage across the bulb is 3 V and its

resistance i, 1R. ( )2

105 Unit 16 Current of Electricity and D.C. Circuits

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v

U,,

Two wires P and Q, each of the same lengthand the same material are connected in parallel

to a cell. The diameter of P is half the diameter

of Q. What fraction of the total current passes

through P?

Bl4

D12

A15

c1J

88. Four resistors are connected as shown in the

diagram.

P 3C)

6c, 6C,

S3C)

Which 2 points when connected to terminalsX and Y in the following circuit will give the

highest reading on the ammeter?

x

A PandQC RandQ

A IOC2

c 1200

B QandSD SandP

B 24f2D 600c)

()

)

()

Y

A heater produces 2.4 kW when a 240 voltsmains supply is connected across it. What isthe resistance of the heater?

Uro.

V,

v2lYOV3Vt2YOV

One of the four identical light bulbs in a series

circuit has blown off as shown. What will be

the voltage readings VrandVr?

t2Y

open circuit

1. Calculate the resistance of the resistor labelledR.

2A

vtlYA 0vB 3VC OVD 3V

A 2AC 6Cl

B 4QD 8Q

()

)

t2f2

4Q

R

106 Unit 16 Cunent of Electricity and D.C. Circuits

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