Current Electricity MCQs

Question 1

A burglar alarm uses an LDR to detect:

Accepted Answer

a change in light when a beam is broken

Answer

heat

Answer

sound

Answer

magnetism

Question 2

Kirchhoff's laws together allow us to:

Accepted Answer

find unknown currents and p.d.s in complex circuits

Answer

design lenses

Answer

measure temperature

Answer

find the mass of electrons

Question 3

The resistance of a wire is:

Accepted Answer

directly proportional to its length and inversely proportional to its area

Answer

independent of its dimensions

Answer

proportional to its area

Answer

inversely proportional to its length

Question 4

Using Kirchhoff's second law, when going through a resistor in the direction of the current, the potential:

Accepted Answer

falls by IR

Answer

does not change

Answer

doubles

Answer

rises by IR

Question 5

Compared with visual inspection, electrical monitoring of carbon-fibre concrete can detect:

Accepted Answer

hidden internal cracks

Answer

only rust colour

Answer

only surface paint damage

Answer

nothing more

Question 6

A battery with large internal resistance is unsuitable for devices that:

Accepted Answer

need large currents

Answer

need tiny currents

Answer

are switched off

Answer

have high resistance

Question 7

An LDR is an example of a:

Accepted Answer

sensor (input transducer)

Answer

output device

Answer

power source

Answer

capacitor

Question 8

For the circuit in the previous question, the p.d. across the 3 Ω resistor is:

Accepted Answer

6 V

Answer

4 V

Answer

3 V

Answer

10 V

Question 9

A cell of e.m.f. 12 V and internal resistance 0.5 Ω is connected to a 5.5 Ω resistor. The terminal p.d. is:

Accepted Answer

11 V

Answer

110 V

Answer

5.5 V

Answer

22 V

Question 10

When an LDR goes from dim to bright light, its conductance:

Accepted Answer

increases

Answer

stays constant

Answer

becomes negative

Answer

decreases

Question 11

A 2 kW heater runs for 3 hours. The energy used is:

Accepted Answer

6 kWh

Answer

1.5 kWh

Answer

6000 kWh

Answer

0.67 kWh

Question 12

This method of monitoring is called:

Accepted Answer

self-sensing (smart) concrete

Answer

X-ray crystallography

Answer

magnetic resonance

Answer

radioactive dating

Question 13

Which material has the lowest resistivity?

Accepted Answer

silver

Answer

glass

Answer

nichrome

Answer

rubber

Question 14

The equation I = Anvq comes from considering:

Accepted Answer

the charge passing a cross-section per second

Answer

the magnetic field

Answer

the energy per charge

Answer

the resistance of the wire

Question 15

A standard cell of e.m.f. 1.5 V balances at 60 cm on a potentiometer wire. Another cell balances at 80 cm. Its e.m.f. is:

Accepted Answer

2 V

Answer

4 V

Answer

1 V

Answer

1.12 V

Question 16

A potential divider with a thermistor gives an output that depends on:

Accepted Answer

temperature

Answer

light intensity

Answer

sound

Answer

pressure

Question 17

The e.m.f. of a cell can be measured approximately by:

Accepted Answer

a high-resistance voltmeter across it when no current is drawn

Answer

a low-resistance voltmeter in a large current

Answer

an ammeter in series

Answer

measuring its mass

Question 18

Charge flows into a junction at 6 C/s. Out of one wire flows 2.5 C/s. The rate of charge flow in the other outgoing wire is:

Accepted Answer

3.5 C/s

Answer

6 C/s

Answer

2.5 C/s

Answer

8.5 C/s

Question 19

A wire of length 1.5 m and diameter 0.3 mm has resistance 12 Ω. Its resistivity is:

Accepted Answer

5.65 10^-7 Ω m

Answer

5.65 10^-6 Ω m

Answer

1.41 10^-7 Ω m

Answer

2.26 10^-6 Ω m

Question 20

In a circuit with a cell of e.m.f. 6 V and two identical resistors in series (negligible internal resistance), the p.d. across each resistor is:

Accepted Answer

3 V

Answer

12 V

Answer

6 V

Answer

2 V

Question 21

Kirchhoff's second law can be written as:

Accepted Answer

sum mathcalE = sum IR

Answer

sum mathcalE = 0

Answer

sum I = 0

Answer

sum R = 0

Question 22

At a junction, currents of 5 A, 3 A flow in. Currents of 6 A flow out, together with one unknown current I. I is:

Accepted Answer

2 A

Answer

20 A

Answer

1 A

Answer

4 A

Question 23

A potentiometer can compare the e.m.f.s of two cells using:

Accepted Answer

mathcalE1mathcalE2 = l1l2

Answer

mathcalE1mathcalE2 = l2l1

Answer

mathcalE1 = l1 + l2

Question 24

A lamp lights almost instantly when switched on, although drift velocity is tiny, because:

Accepted Answer

the electric field travels through the circuit at nearly the speed of light, moving all electrons at once

Answer

current flows only in the lamp

Answer

the lamp stores charge

Answer

electrons move at the speed of light

Question 25

A solar cell's e.m.f. comes from converting:

Accepted Answer

light energy into electrical energy

Answer

nuclear energy

Answer

chemical energy

Answer

kinetic energy

Current Electricity MCQs — Physics (page 2)

26. A burglar alarm uses an LDR to detect:

27. Kirchhoff's laws together allow us to:

28. The resistance of a wire is:

29. Using Kirchhoff's second law, when going through a resistor in the direction of the current, the potential:

30. Compared with visual inspection, electrical monitoring of carbon-fibre concrete can detect:

31. A battery with large internal resistance is unsuitable for devices that:

32. An LDR is an example of a:

33. For the circuit in the previous question, the p.d. across the 3 Ω resistor is:

34. A cell of e.m.f. 12 V and internal resistance 0.5 Ω is connected to a 5.5 Ω resistor. The terminal p.d. is:

35. When an LDR goes from dim to bright light, its conductance:

36. A 2 kW heater runs for 3 hours. The energy used is:

37. This method of monitoring is called:

38. Which material has the lowest resistivity?

39. The equation I = Anvq comes from considering:

40. A standard cell of e.m.f. 1.5 V balances at 60 cm on a potentiometer wire. Another cell balances at 80 cm. Its e.m.f. is:

41. A potential divider with a thermistor gives an output that depends on:

42. The e.m.f. of a cell can be measured approximately by:

43. Charge flows into a junction at 6 C/s. Out of one wire flows 2.5 C/s. The rate of charge flow in the other outgoing wire is:

44. A wire of length 1.5 m and diameter 0.3 mm has resistance 12 Ω. Its resistivity is:

45. In a circuit with a cell of e.m.f. 6 V and two identical resistors in series (negligible internal resistance), the p.d. across each resistor is:

46. Kirchhoff's second law can be written as:

47. At a junction, currents of 5 A, 3 A flow in. Currents of 6 A flow out, together with one unknown current I. I is:

48. A potentiometer can compare the e.m.f.s of two cells using:

49. A lamp lights almost instantly when switched on, although drift velocity is tiny, because:

50. A solar cell's e.m.f. comes from converting:

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