Current Electricity MCQs

Question 1

A galvanometer can be converted into a voltmeter by:

Accepted Answer

connecting a large resistance in series

Answer

connecting a small shunt in parallel

Answer

removing its magnet

Answer

connecting a capacitor

Question 2

An LDR in a circuit is most like:

Accepted Answer

a variable resistor controlled by light

Answer

a cell

Answer

a switch controlled by heat

Answer

a fixed resistor

Question 3

If the galvanometer deflects to the left at one end of the wire and to the right at the other, then:

Accepted Answer

a balance point exists between them

Answer

there is no balance point

Answer

the cell is flat

Answer

the galvanometer is broken

Question 4

The resistance of a light-dependent resistor (LDR):

Accepted Answer

decreases as light intensity increases

Answer

depends only on temperature

Answer

increases as light intensity increases

Answer

is constant

Question 5

A battery of e.m.f. 6 V has a terminal p.d. of 5 V when delivering 2 A. Its internal resistance is:

Accepted Answer

0.5 Ω

Answer

2.5 Ω

Answer

0.25 Ω

Answer

1 Ω

Question 6

The unit of power, the watt, equals:

Accepted Answer

1 J/s

Answer

1 C/s

Answer

1 V/A

Answer

1 J s

Question 7

A charge of 3 C moves through a p.d. of 12 V. The energy transferred is:

Accepted Answer

36 J

Answer

18 J

Answer

4 J

Answer

72 J

Question 8

As the current drawn from a battery increases, its terminal p.d.:

Accepted Answer

decreases

Answer

becomes equal to the e.m.f.

Answer

increases

Answer

stays constant

Question 9

A source of e.m.f. 6 V and internal resistance 0.5 Ω drives a 2.5 Ω load. The power delivered to the load is:

Accepted Answer

10 W

Answer

5 W

Answer

100 W

Answer

20 W

Question 10

A device draws 5 A from a 9 V supply. Its power is:

Accepted Answer

45 W

Answer

90 W

Answer

22.5 W

Answer

1.8 W

Question 11

A potential divider has 10 kΩ and 5 kΩ resistors in series across 9 V. The p.d. across the 5 kΩ resistor is:

Accepted Answer

3 V

Answer

30 V

Answer

6 V

Answer

1.5 V

Question 12

A copper wire has n = 1 10^29 m^-3, cross-section 5 10^-7 m^2 and drift velocity 2 10^-4 m/s. The current is (e = 1.6 10^-19 C):

Accepted Answer

1.6 A

Answer

0.16 A

Answer

16 A

Answer

3.2 A

Question 13

An LDR's resistance might change from about 1 MΩ in the dark to:

Accepted Answer

a few hundred ohms in bright light

Answer

1 MΩ unchanged

Answer

infinity

Answer

10 MΩ in bright light

Question 14

A galvanometer with a centre-zero scale is useful because:

Accepted Answer

it shows current in either direction

Answer

it measures voltage only

Answer

it measures very large currents

Answer

it never deflects

Question 15

Old-style fairy lights in series all go out when one bulb fails because:

Accepted Answer

the circuit is broken, so no current flows

Answer

the other bulbs blow

Answer

the voltage rises

Answer

the current increases

Question 16

Resistors of 100 Ω, 220 Ω, 330 Ω are connected in series. The combined resistance is:

Accepted Answer

650 Ω

Answer

1300 Ω

Answer

6500 Ω

Answer

325 Ω

Question 17

In a potential divider with two equal resistors across 10 V, the output across one is:

Accepted Answer

5 V

Answer

10 V

Answer

2.5 V

Answer

20 V

Question 18

Semiconductors have a much smaller n than metals, so for the same current and area their drift velocity is:

Accepted Answer

much larger

Answer

zero

Answer

much smaller

Answer

the same

Question 19

A galvanometer can be converted into an ammeter by:

Accepted Answer

connecting a small resistance (shunt) in parallel

Answer

adding a battery

Answer

removing its coil

Answer

connecting a large resistance in series

Question 20

The circuit symbol for an LDR is:

Accepted Answer

a resistor with arrows pointing towards it

Answer

a diode

Answer

a resistor with arrows pointing away

Answer

a circle with a cross

Question 21

In a series circuit, the p.d. across each resistor is:

Accepted Answer

proportional to its resistance

Answer

inversely proportional to its resistance

Answer

zero

Answer

the same for all resistors

Question 22

In a complete circuit, the sum of the p.d.s around the loop equals:

Accepted Answer

the sum of the e.m.f.s

Answer

the current

Answer

zero always

Answer

the resistance

Question 23

A wire has resistivity 4.9 10^-7 Ω m, length 2 m and cross-section 5 10^-7 m^2. Its resistance is:

Accepted Answer

1.96 Ω

Answer

3.92 Ω

Answer

19.6 Ω

Answer

0.196 Ω

Question 24

Inspectors can easily check the bridge because the method needs only:

Accepted Answer

simple electrical measurements at connection points

Answer

heavy cranes

Answer

divers

Answer

dismantling the bridge

Question 25

Resistors of 10 Ω, 40 Ω are connected in parallel. The combined resistance is:

Accepted Answer

8 Ω

Answer

16 Ω

Answer

4 Ω

Answer

80 Ω

Current Electricity MCQs — Physics (page 10)

226. A galvanometer can be converted into a voltmeter by:

227. An LDR in a circuit is most like:

228. If the galvanometer deflects to the left at one end of the wire and to the right at the other, then:

229. The resistance of a light-dependent resistor (LDR):

230. A battery of e.m.f. 6 V has a terminal p.d. of 5 V when delivering 2 A. Its internal resistance is:

231. The unit of power, the watt, equals:

232. A charge of 3 C moves through a p.d. of 12 V. The energy transferred is:

233. As the current drawn from a battery increases, its terminal p.d.:

234. A source of e.m.f. 6 V and internal resistance 0.5 Ω drives a 2.5 Ω load. The power delivered to the load is:

235. A device draws 5 A from a 9 V supply. Its power is:

236. A potential divider has 10 kΩ and 5 kΩ resistors in series across 9 V. The p.d. across the 5 kΩ resistor is:

237. A copper wire has n = 1 10^29 m^-3, cross-section 5 10^-7 m^2 and drift velocity 2 10^-4 m/s. The current is (e = 1.6 10^-19 C):

238. An LDR's resistance might change from about 1 MΩ in the dark to:

239. A galvanometer with a centre-zero scale is useful because:

240. Old-style fairy lights in series all go out when one bulb fails because:

241. Resistors of 100 Ω, 220 Ω, 330 Ω are connected in series. The combined resistance is:

242. In a potential divider with two equal resistors across 10 V, the output across one is:

243. Semiconductors have a much smaller n than metals, so for the same current and area their drift velocity is:

244. A galvanometer can be converted into an ammeter by:

245. The circuit symbol for an LDR is:

246. In a series circuit, the p.d. across each resistor is:

247. In a complete circuit, the sum of the p.d.s around the loop equals:

248. A wire has resistivity 4.9 10^-7 Ω m, length 2 m and cross-section 5 10^-7 m^2. Its resistance is:

249. Inspectors can easily check the bridge because the method needs only:

250. Resistors of 10 Ω, 40 Ω are connected in parallel. The combined resistance is:

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