electric current and magnetism - Category wise Question and Answer Practice Test with Solutions

Question : 11 [IAS (Pre) 1999]

Consider the following statements. An ordinary light bulb has a rather short life because the

1. Filament wire is not uniform.
2. Bulb cannot be evacuated completely.
3. Wires supporting the filament melt at high temperatures.

a) 1 and 3

b) 1 and 3

c) 2 and 3

d) 1, 2 and 3

Question : 12 [IAS Prelim]

Graphene is frequently in news recently. What is its importance?

1. It is a two-dimensional material and has good electrical conductivity.
2. It is one of the thinnest but strongest materials tested so far.
3. It is entirely made of silicon and has high optical transparency.
4. It can be used as ‘conducting electrodes’ required for touch screens, LCDs and organic LEDs.

a) 1, 2 and 4 only

b) 1 and 2 only

c) 3 and 4 only

d) 1, 2, 3 and 4

Question : 13

In a p-n junction

a) the p side is at higher electrical potential than n side

b) the n side is at higher electric potential than p side

c) the potential of p & n sides becomes higher alternately

d) both p & n sides are at same potential

Question : 14 [NDA]

Match list-I with list -II:

a) 2 1 4 3

b) 3 1 4 2

c) 3 4 1 2

d) 2 4 1 3

Question : 15 [NDA]

Which one among the following is the correct order of power consumption for light of equal intensity ?

a) CFL tube < Fluorescent tube < Light emitting diode < Incandescent bulb

b) CFL tube < Fluorescent tube < Incandescent bulb < Light emitting diode

c) Light emitting diode < CFL tube < Fluorescent tube < Incandescent bulb

d) Incandescent bulb < Light emitting diode < Fluorescent tube < CFL tube