B1, B2 and B3 are the three identical bulbs connected to a battery of steady e.m.f. with key K closed. What happens to the brightness of the bulbs B1 and B2 when the key is opened?

Question

B1, B2 and B3 are the three identical bulbs connected to a battery of steady e.m.f. with key K closed. What happens to the brightness of the bulbs B1 and B2 when the key is opened? (A) Brightness of the bulb, B1 decreases and that of B2 increases. (B) Brightness of the bulbs B1 and B2 decreases. (C) Brightness of the bulbs B1 increases and that of B2 decreases (D) Brightness of the bulbs B1 and B2 increases.

Tardigrade Admin · Accepted Answer

When key K is opened, bulb B2 will not draw any current from the source, so that terminal voltage of source increases. Hence, power consumed by bulb increases, so light of the bulb becomes more. The brightness of bulb B1 decreases.

Q. $B_{1}$ , $B_{2}$ and $B_{3}$ are the three identical bulbs connected to a battery of steady e.m.f. with key $K$ closed. What happens to the brightness of the bulbs $B_{1}$ and $B_{2}$ when the key is opened?

Brightness of the bulb, $B_{1}$ decreases and that of $B_{2}$ increases.

Brightness of the bulbs $B_{1}$ and $B_{2}$ decreases.

Brightness of the bulbs $B_{1}$ increases and that of $B_{2}$ decreases

Brightness of the bulbs $B_{1}$ and $B_{2}$ increases.

When key $K$ is opened, bulb $B_{2}$ will not draw any current from the source, so that terminal voltage of source increases. Hence, power consumed by bulb increases, so light of the bulb becomes more. The brightness of bulb $B_{1}$ decreases.

Q. B1​, B2​ and B3​ are the three identical bulbs connected to a battery of steady e.m.f. with key K closed. What happens to the brightness of the bulbs B1​ and B2​ when the key is opened?

Brightness of the bulb, B1​ decreases and that of B2​ increases.

Brightness of the bulbs B1​ and B2​ decreases.

Brightness of the bulbs B1​ increases and that of B2​ decreases

Brightness of the bulbs B1​ and B2​ increases.