The amount of heat produced in a wire on passing a current through it depends on:

1. the resistance of wire
2. the square root of current I passing through the wire.
3. the time for which current is passed.
4. Both (1) and (3)

An electrical appliance has a rating 100 W, 120 V. The resistance of element of appliance when in use is —

1. 1.2 Ω
2. 144 Ω
3. 120 Ω
4. 100 Ω

Three bulbs A, B and C are connected as shown in the figure. What changes are seen in brightness of the bulbs if switch S is closed?

1. The brightness of bulb A decreases and that of C increases.
2. The brightness of bulb A increases but that of C decreases.
3. The brightness of both bulbs A and C decreases.
4. The brightness of both bulbs A and C remains the same.

A bulb B₁ 100 W, bulb B₂ 60 W and bulb B₃ 40 W are connected as shown in the figure. The output powers of these would be :

1. W₁ < W₂ < W₃
2. W₁ = W₂ > W₃
3. W₁ > W₂ > W₃
4. W₁ > W₂ = W₃