Question

Bulb $1$ and Bulb $2$ are rated ($30\text{W}-200\text{V}$) and ($60\text{W}-200\text{V}$) respectively. They are connected with a $400\text{V}$ power supply. Find which bulb will get fused if they are connected in parallel.

• A. Bulb $1$ will get fused.
• B. Bulb $2$ will get fused.
• C. Both will get fused.
• D. No bulb will get fused.

Answer 1

The correct option is C Both will get fused.

In parallel, potential across both the bulbs will be same and equal to $400\text{V}$.

So both will get fused because voltage rating for both the bulb is $200\text{V}$ only.

So, the right option is $\left(c\right)$.

Why this question ? Key concept: If actual voltage across a device exceeds its voltage rating it is likely to get damaged.