Current Electricity MCQs

Question 1

A charge of 0.5 C moves through a p.d. of 230 V. The energy transferred is:

Accepted Answer

115 J

Answer

230 J

Answer

460 J

Answer

57.5 J

Question 2

Resistors of 4 Ω, 4 Ω, 4 Ω, 4 Ω are connected in series. The combined resistance is:

Accepted Answer

16 Ω

Answer

32 Ω

Answer

160 Ω

Answer

8 Ω

Question 3

A wire has resistivity 1.1 10^-6 Ω m, length 0.5 m and cross-section 2 10^-7 m^2. Its resistance is:

Accepted Answer

2.75 Ω

Answer

0.275 Ω

Answer

27.5 Ω

Answer

5.5 Ω

Question 4

At a junction, currents of 2.5 A flow in. Currents of 1.2 A, 0.3 A flow out, together with one unknown current I. I is:

Accepted Answer

1 A

Answer

2 A

Answer

0.5 A

Answer

10 A

Question 5

A 6 V battery is connected across three 2 Ω resistors in parallel. The battery current is:

Accepted Answer

9 A

Answer

0.67 A

Answer

1 A

Answer

3 A

Question 6

A potentiometer wire is 1 m long with 2 V across it. The potential gradient is:

Accepted Answer

2 V/m

Answer

200 V/m

Answer

2 V/cm

Answer

0.5 V/m

Question 7

A 12 V cell with negligible internal resistance is connected to a 4 Ω resistor in series with a parallel pair of 6 Ω and 3 Ω. The current from the cell is:

Accepted Answer

2 A

Answer

3 A

Answer

1 A

Answer

0.92 A

Question 8

A circuit has a 9 V cell, internal resistance 1 Ω, and an external 8 Ω resistor. The current is:

Accepted Answer

1 A

Answer

9 A

Answer

0.89 A

Answer

1.125 A

Question 9

When a car's starter motor is operated, the headlights dim because:

Accepted Answer

the large current causes a big p.d. across the battery's internal resistance

Answer

the headlights are disconnected

Answer

the motor produces light

Answer

the battery's e.m.f. increases

Question 10

A cell of e.m.f. 1.5 V and internal resistance 0.5 Ω is connected to a 2.5 Ω resistor. The terminal p.d. is:

Accepted Answer

1.25 V

Answer

0.625 V

Answer

2.5 V

Answer

12.5 V

Question 11

Adding another resistor in series to a circuit makes the current:

Accepted Answer

decrease

Answer

increase

Answer

stay the same

Answer

reverse

Question 12

Ordinary concrete without fibres is a:

Accepted Answer

poor conductor of electricity

Answer

good conductor

Answer

magnet

Answer

superconductor

Question 13

A 3 Ω resistor is connected to 9 V. The power is:

Accepted Answer

27 W

Answer

28 W

Answer

3 W

Answer

54 W

Question 14

Measuring resistance to detect damage is useful because it:

Accepted Answer

is quick and doesn't need the bridge to be broken open

Answer

needs the bridge to be closed for months

Answer

requires removing the concrete

Answer

needs X-ray equipment

Question 15

A current of 10 A flows through a 0.5 Ω resistor. The power dissipated is:

Accepted Answer

50 W

Answer

100 W

Answer

5 W

Answer

25 W

Question 16

A generator produces e.m.f. by converting:

Accepted Answer

mechanical energy into electrical energy

Answer

electrical into mechanical

Answer

heat into chemical energy

Answer

light into sound

Question 17

Embedding sensors in structures for continuous checking is called:

Accepted Answer

structural health monitoring

Answer

power generation

Answer

radio broadcasting

Answer

electroplating

Question 18

In I = Anvq, n stands for:

Accepted Answer

the number of charge carriers per unit volume

Answer

the number of turns

Answer

the number of electrons in the wire

Answer

the refractive index

Question 19

Two cells, 6 V and 4 V, are connected in series opposing with a 5 Ω resistor. The current is:

Accepted Answer

0.4 A

Answer

1.2 A

Answer

2 A

Answer

0.8 A

Question 20

Two identical cells in parallel compared with one cell give:

Accepted Answer

the same e.m.f. but half the internal resistance

Answer

double the e.m.f.

Answer

double the internal resistance

Answer

zero e.m.f.

Question 21

The potential difference between two points is:

Accepted Answer

the energy transferred per unit charge passing between them

Answer

the current per unit time

Answer

the charge per unit energy

Answer

the force per unit charge

Question 22

A 24 V supply drives current through 3 Ω and R in series; the current is 2 A. R is:

Accepted Answer

9 Ω

Answer

12 Ω

Answer

6 Ω

Answer

3 Ω

Question 23

A current of 5 A flows in a wire with n = 8.5 10^28 m^-3 and area 3 10^-6 m^2. The drift velocity of the electrons is:

Accepted Answer

1.23 10^-4 m/s

Answer

2.45 10^-4 m/s

Answer

0.00123 m/s

Answer

1.23 10^-5 m/s

Question 24

Taking currents into a junction as positive, Kirchhoff's first law can be written as:

Accepted Answer

sum I = 0

Answer

sum IR = sum mathcalE

Answer

sum I = 1

Answer

sum V = 0

Question 25

Which instrument uses a galvanometer in a null method?

Accepted Answer

a potentiometer

Answer

a thermometer

Answer

a voltmeter across a lamp

Answer

an ammeter in series

Current Electricity MCQs — Physics (page 8)

176. A charge of 0.5 C moves through a p.d. of 230 V. The energy transferred is:

177. Resistors of 4 Ω, 4 Ω, 4 Ω, 4 Ω are connected in series. The combined resistance is:

178. A wire has resistivity 1.1 10^-6 Ω m, length 0.5 m and cross-section 2 10^-7 m^2. Its resistance is:

179. At a junction, currents of 2.5 A flow in. Currents of 1.2 A, 0.3 A flow out, together with one unknown current I. I is:

180. A 6 V battery is connected across three 2 Ω resistors in parallel. The battery current is:

181. A potentiometer wire is 1 m long with 2 V across it. The potential gradient is:

182. A 12 V cell with negligible internal resistance is connected to a 4 Ω resistor in series with a parallel pair of 6 Ω and 3 Ω. The current from the cell is:

183. A circuit has a 9 V cell, internal resistance 1 Ω, and an external 8 Ω resistor. The current is:

184. When a car's starter motor is operated, the headlights dim because:

185. A cell of e.m.f. 1.5 V and internal resistance 0.5 Ω is connected to a 2.5 Ω resistor. The terminal p.d. is:

186. Adding another resistor in series to a circuit makes the current:

187. Ordinary concrete without fibres is a:

188. A 3 Ω resistor is connected to 9 V. The power is:

189. Measuring resistance to detect damage is useful because it:

190. A current of 10 A flows through a 0.5 Ω resistor. The power dissipated is:

191. A generator produces e.m.f. by converting:

192. Embedding sensors in structures for continuous checking is called:

193. In I = Anvq, n stands for:

194. Two cells, 6 V and 4 V, are connected in series opposing with a 5 Ω resistor. The current is:

195. Two identical cells in parallel compared with one cell give:

196. The potential difference between two points is:

197. A 24 V supply drives current through 3 Ω and R in series; the current is 2 A. R is:

198. A current of 5 A flows in a wire with n = 8.5 10^28 m^-3 and area 3 10^-6 m^2. The drift velocity of the electrons is:

199. Taking currents into a junction as positive, Kirchhoff's first law can be written as:

200. Which instrument uses a galvanometer in a null method?

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