physics MCQs - 10th class Chapter 05 Mcqs

1

An electric current in metallic conductors is due to the flow of

A

positive ions

B

negative ions

C

free electrons

D

positive charges

2

The rate of flow of electric charge through any cross-sectional area is called

A

potential difference

B

resistance

C

power

D

current

3

The SI unit for electric current is

A

Volt (V)

B

Ohm (Ω)

C

Ampere (A)

D

Watt (W)

4

If a charge of one coulomb passes through a cross-sectional area in one second, the current is

A

one volt

B

one ampere

C

one ohm

D

one watt

5

A source that converts chemical energy into electrical energy is a

A

generator

B

thermocouple

C

motor

D

battery

6

The flow of current from the positive to the negative terminal of a battery is called

A

electronic current

B

alternating current

C

direct current

D

conventional current

7

Which instrument is used to detect small electric currents?

A

Ammeter

B

Voltmeter

C

Galvanometer

D

Multimeter

8

To measure the total current flowing in a series circuit, an ammeter should be connected in

A

series

B

parallel

C

across the battery

D

across the resistor

9

An ideal voltmeter should have a very

A

low resistance

B

high resistance

C

low voltage

D

high current

10

The SI unit of potential difference is

A

Ampere

B

Ohm

C

Joule

D

Volt

11

The energy supplied by a battery to a unit positive charge when it flows through a closed circuit is called

A

potential difference

B

resistance

C

power

D

e.m.f.

12

Ohm's law states that

A

V = I/R

B

I = VR

C

V = IR

D

R = VI

13

The property of a substance which offers opposition to the flow of current is its

A

conductance

B

current

C

voltage

D

resistance

14

The SI unit of resistance, represented by the symbol Ω, is

A

Volt

B

Ampere

C

Ohm

D

Watt

15

Materials that obey Ohm's law and have a constant resistance are called

A

non-ohmic

B

ohmic

C

insulators

D

superconductors

16

The V-I graph for an ohmic conductor is a

A

curved line

B

straight line

C

parabola

D

circle

17

The resistance of a filament lamp ________ as it gets hotter.

A

decreases

B

remains constant

C

increases

D

becomes zero

18

The resistance of a thermistor ________ as it gets hotter.

A

increases

B

decreases

C

remains constant

D

becomes infinite

19

The resistance of a wire is directly proportional to its

A

cross-sectional area

B

thickness

C

diameter

D

length

20

A thick wire has ________ resistance than a thin wire.

A

more

B

less

C

the same

D

zero

21

The specific resistance of a substance depends on the

A

length of the wire

B

area of the wire

C

nature of the conductor

D

current flowing

22

The SI unit of specific resistance (ρ) is

A

Ohm (Ω)

B

Ohm-meter (Ωm)

C

Ohm per meter (Ω/m)

D

Meter per Ohm (m/Ω)

23

Materials that have no free electrons and do not conduct electricity are known as

A

conductors

B

semiconductors

C

alloys

D

insulators

24

The resistance of conductors generally ________ with an increase in temperature.

A

decreases

B

increases

C

remains the same

D

disappears

25

In a series combination of resistors, the ________ is the same through each resistor.

A

voltage

B

resistance

C

power

D

current

26

For three resistors R1, R2, and R3 connected in series, the equivalent resistance Re is

A

R1 + R2 + R3

B

1/R1 + 1/R2 + 1/R3

C

(R1*R2*R3)/(R1+R2+R3)

D

1/(R1 + R2 + R3)

27

In a parallel combination of resistors, the ________ is the same across each resistor.

A

current

B

resistance

C

voltage

D

charge

28

For three resistors R1, R2, and R3 connected in parallel, the equivalent resistance Re is given by

A

Re = R1+R2+R3

B

1/Re = 1/R1 + 1/R2 + 1/R3

C

Re = 1/R1 + 1/R2 + 1/R3

D

1/Re = R1+R2+R3

29

Household appliances are typically connected in

A

series

B

parallel

C

a combination of series and parallel

D

a grid

30

Joule's law states that the heat generated in a resistance is equal to

A

IRt

B

I²Rt

C

V²/R

D

VIt²

31

The amount of energy supplied by a current in unit time is known as

A

electrical energy

B

voltage

C

electric power

D

resistance

32

The SI unit of electric power is

A

Joule (J)

B

Watt (W)

C

Kilowatt-hour (kWh)

D

Ampere (A)

33

One kilowatt-hour (kWh) is a unit of

A

power

B

current

C

resistance

D

energy

34

1 kWh is equal to

A

3.6 J

B

3600 J

C

3.6 MJ

D

36 MJ

35

The current derived from a battery is

A

alternating current (a.c.)

B

variable current

C

direct current (d.c.)

D

pulsating current

36

The frequency of alternating current (AC) supplied in Pakistan is

A

60 Hz

B

50 Hz

C

100 Hz

D

220 Hz

37

In house wiring, the wire at high potential (220V) is the

A

neutral wire

B

earth wire

C

live wire

D

ground wire

38

The wire maintained at zero potential in a domestic supply is the

A

live wire

B

earth wire

C

positive wire

D

neutral wire

39

A safety device that consists of a thin wire which melts and breaks a circuit if the current is too high is a

A

circuit breaker

B

switch

C

fuse

D

resistor

40

A circuit breaker functions as a safety device by acting as an automatic

A

resistor

B

capacitor

C

switch

D

voltmeter

41

The purpose of the earth wire is to

A

provide high potential

B

provide a return path for current

C

prevent electric shock from faulty appliances

D

increase the circuit's resistance

42

A short circuit occurs when a circuit with a very ________ resistance is formed.

A

high

B

low

C

medium

D

infinite

43

Operating electrical appliances with wet hands is dangerous because damp conditions drastically ________ human skin's resistance.

A

increase

B

reduce

C

do not change

D

stabilize

44

What is the power of a bulb that consumes 2400 J of electrical energy in 40 s?

A

60 W

B

9600 W

C

0.016 W

D

2440 W

45

What is the voltage across a 6 Ω resistor when 3 A of current passes through it?

A

2 V

B

9 V

C

18 V

D

36 V

46

When we double the voltage in a simple electric circuit, we double the

A

resistance

B

power

C

current

D

capacitance

47

The combined resistance of two identical resistors connected in series is 8 Ω. Their combined resistance in a parallel arrangement will be

A

4 Ω

B

8 Ω

C

12 Ω

D

2 Ω

48

Electric potential and e.m.f are

A

the same terms

B

different terms

C

have different units

D

both (b) and (c)

49

If a current of 3 mA flows for 1 minute, the charge that has passed is

A

3 mC

B

180 mC

C

0.05 C

D

3 C

50

The resistance of an incandescent bulb with an operating resistance of 95 Ω and labelled "150 W" is designed for a circuit of approximately

A

220 V

B

120 V

C

100 V

D

50 V