CBSE X Electricity practice questions

Question 1

A wire carries 10²¹ electrons in 4 minutes. Find the current to one decimal place; electron charge=1.6×10⁻¹⁹ C.

Accepted Answer

0.7 A

Answer

40 A

Answer

7 A

Answer

4 A

Question 2

Assertion (A): A conducting wire must have a nonzero net electric charge to carry current.
Reason (R): In a metallic wire,current involves directional drift of free electrons.

Accepted Answer

A is false but R is true.

Answer

Both A and R are true and R explains A.

Answer

Both A and R are true but R does not explain A.

Answer

A is true but R is false.

Question 3

Measured pairs(V,I) are(1.0,0.1),(2.2,0.2),(3.0,0.6),(4.0,0.4),(6.4,0.6). Which pair is the clear resistance outlier?

Accepted Answer

(3.0 V,0.6 A)

Answer

(1.0 V,0.1 A)

Answer

(2.2 V,0.2 A)

Answer

(6.4 V,0.6 A)

Question 4

How is an ammeter connected to measure current through a circuit branch?

Accepted Answer

In series with that branch

Answer

In parallel across the source

Answer

Across an open switch only

Answer

With both terminals attached to the same point

Question 5

For identical bulbs with the same voltage and wattage ratings connected in series, what is true at corresponding steady operating conditions?

Accepted Answer

Both current and voltage drop are the same for each bulb

Answer

Current is different but voltage is the same

Answer

Voltage is different but current is the same

Answer

Both must be different

Question 6

A 100 W,220 V lamp has hot resistance ten times its cold resistance. Find its cold resistance.

Accepted Answer

48.4 Ω

Answer

48 Ω

Answer

400 Ω

Answer

484 Ω

Question 7

Why are high-power appliances commonly supplied on appropriately rated separate domestic circuits?

Accepted Answer

Their larger currents require suitable conductors and protective devices

Answer

High-power appliances require no protection

Answer

Every appliance draws exactly the same current

Answer

Separate circuits make energy consumption zero

Question 8

To measure current and voltage for a 1 m wire AB,how should the ammeter and voltmeter be connected?

Accepted Answer

Ammeter in series with AB;voltmeter in parallel across AB

Answer

Both in series

Answer

Both across an open key

Answer

Ammeter in parallel and voltmeter in series