Current Electricity MCQs

Question 1

A steady rise in a bridge's measured resistance over months suggests:

Accepted Answer

growing damage or cracking

Answer

the bridge is getting stronger

Answer

it is raining

Answer

the voltage is too high

Question 2

A circuit has cells of e.m.f. 3 V and 1.5 V in parallel (same polarity) with internal resistances 1 Ω each. The current circulating between them (no external load) is:

Accepted Answer

0.75 A

Answer

2.25 A

Answer

4.5 A

Answer

1.5 A

Question 3

In a circuit, charges gain energy in the and lose energy in the .

Accepted Answer

source; external components

Answer

source; source

Answer

components; source

Answer

wires; source

Question 4

A cell transfers 240 J of energy to 20 C of charge driven round a complete circuit. Its e.m.f. is:

Accepted Answer

12 V

Answer

6 V

Answer

24 V

Answer

4800 V

Question 5

A potentiometer measures the e.m.f. of a cell accurately because:

Accepted Answer

no current is drawn from the cell at balance

Answer

it measures the internal resistance

Answer

it uses a large current

Answer

it has a low resistance

Question 6

A cell of e.m.f. 12 V drives a current of 2 A. The power supplied by the cell is:

Accepted Answer

24 W

Answer

14 W

Answer

12 W

Answer

6 W

Question 7

A potential divider has 2.2 kΩ and 3.3 kΩ resistors in series across 5 V. The p.d. across the 3.3 kΩ resistor is:

Accepted Answer

3 V

Answer

6 V

Answer

1.5 V

Answer

30 V

Question 8

Mains power supplies are designed with very low internal resistance so that:

Accepted Answer

the voltage stays nearly constant as the load changes

Answer

they produce no current

Answer

they get hot

Answer

they are safer to touch

Question 9

In a loop containing two cells opposing each other (6 V and 2 V), the net e.m.f. is:

Accepted Answer

4 V

Answer

8 V

Answer

12 V

Answer

3 V

Question 10

If a calculated current in a Kirchhoff's law problem comes out negative, it means:

Accepted Answer

the actual current flows opposite to the direction assumed

Answer

the resistor is faulty

Answer

no current flows

Answer

the answer is wrong

Question 11

A current of 3 A flows through a 4 Ω resistor. The power dissipated is:

Accepted Answer

36 W

Answer

72 W

Answer

18 W

Answer

12 W

Question 12

9 J of energy is transferred when 0.75 C of charge passes between two points. The p.d. is:

Accepted Answer

12 V

Answer

6.75 V

Answer

6 V

Answer

24 V

Question 13

In a Wheatstone bridge, the galvanometer reads zero when:

Accepted Answer

PQ = RS

Answer

PQ = RS + 1

Answer

P + Q = R + S

Answer

P = S

Question 14

Sources of e.m.f. convert:

Accepted Answer

other forms of energy into electrical energy

Answer

charge into energy

Answer

electrical energy into light only

Answer

electrical energy into heat

Question 15

A 12 V battery (no internal resistance) is connected to three resistors in series. The p.d.s across two of them are 5 V and 4 V. The p.d. across the third is:

Accepted Answer

3 V

Answer

6 V

Answer

30 V

Answer

1.5 V

Question 16

As a battery ages, its internal resistance usually:

Accepted Answer

increases

Answer

stays constant

Answer

becomes zero

Answer

decreases

Question 17

E.m.f. refers to energy transferred:

Accepted Answer

into electrical energy by a source

Answer

only as heat

Answer

from electrical energy in a component

Answer

into chemical energy in a resistor

Question 18

An advantage of carbon-fibre concrete monitoring is that it can give:

Accepted Answer

early warning before visible failure

Answer

infinite strength

Answer

self-repair

Answer

zero maintenance cost

Question 19

A torch bulb dims when the batteries are old because:

Accepted Answer

their internal resistance has increased

Answer

the bulb's resistance becomes zero

Answer

their e.m.f. becomes larger

Answer

the wires get longer

Question 20

A current of 0.5 A flows for 60 s through a p.d. of 12 V. The energy transferred is:

Accepted Answer

360 J

Answer

180 J

Answer

720 J

Answer

6 J

Current Electricity MCQs — Physics (page 11)

251. A steady rise in a bridge's measured resistance over months suggests:

252. A circuit has cells of e.m.f. 3 V and 1.5 V in parallel (same polarity) with internal resistances 1 Ω each. The current circulating between them (no external load) is:

253. In a circuit, charges gain energy in the and lose energy in the .

254. A cell transfers 240 J of energy to 20 C of charge driven round a complete circuit. Its e.m.f. is:

255. A potentiometer measures the e.m.f. of a cell accurately because:

256. A cell of e.m.f. 12 V drives a current of 2 A. The power supplied by the cell is:

257. A potential divider has 2.2 kΩ and 3.3 kΩ resistors in series across 5 V. The p.d. across the 3.3 kΩ resistor is:

258. Mains power supplies are designed with very low internal resistance so that:

259. In a loop containing two cells opposing each other (6 V and 2 V), the net e.m.f. is:

260. If a calculated current in a Kirchhoff's law problem comes out negative, it means:

261. A current of 3 A flows through a 4 Ω resistor. The power dissipated is:

262. 9 J of energy is transferred when 0.75 C of charge passes between two points. The p.d. is:

263. In a Wheatstone bridge, the galvanometer reads zero when:

264. Sources of e.m.f. convert:

265. A 12 V battery (no internal resistance) is connected to three resistors in series. The p.d.s across two of them are 5 V and 4 V. The p.d. across the third is:

266. As a battery ages, its internal resistance usually:

267. E.m.f. refers to energy transferred:

268. An advantage of carbon-fibre concrete monitoring is that it can give:

269. A torch bulb dims when the batteries are old because:

270. A current of 0.5 A flows for 60 s through a p.d. of 12 V. The energy transferred is:

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