Question

Figure shows that bulbs B${}_1$, B${}_2$ and B${}_3$ are connected to the mains. Suppose B${}_4$ is another bulb added in parallel, then

• A. The brightness of B${}_1$ will increase.
• B. The brightness of B${}_3$ will increase.
• C. The brightness of both B${}_1$ and B${}_2$ will increase.
• D. The brightness of both B${}_1$ and B${}_2$ will fall.

Answer 1

The correct option is B The brightness of B${}_3$ will increase.

when we connect any bulb or resistor in parallel /overall resistance gets decreased.In this circuit total resistance gets decreased due by connected in parallel and current is inversely proportional ti resistance. Total current will pass through $B_3$

Hence resistance gets decreased and total current will increase. Brightness of $B_3$ will increase.