Question

A factory is served by a $220\text{V}$ supply line. In a circuit protected by a fuse marked $10\text{A}$, the maximum number of $100\text{W}$ lamps in parallel that can be turned on is

• A. $11$
• B. $22$
• C. $33$
• D. $66$

Answer 1

The correct option is B $22$

Current required by each bulb,

$I=\frac{P}{V}=\frac{100}{220}\text{A}$

If $\text{n}$ bulbs are joined in parallel, then

$\text{n}I=I_{fuse}$
$\text{n}\times \frac{100}{220}=10$
$\text{n}=22$

Key concept: In parallel combination of light bulbs, potential difference across each bulb remains same.