Question

A house wiring, supplied with a 220 V supply line, is protected by a 9 amp. fuse. The maximum number of 60 W bulbs in parallel that can be turned on is

• A. 44
• B. 33
• C. 22
• D. 11

Answer 1

The correct option is B 33

Given that,
$V=220$ V
$I=9$ A
$P=60$ W
We have,
$P=\frac{V^2}{R}$
$\frac{P}{V}=\frac{V}{R}=I$
Let, the maximum number of 60 W bulbs in parallel that can be turned on is $n$,
Therefore,
$n\times \frac{P}{V}=I$
$n=I\times \frac{V}{P}$
$n=9\times \frac{220}{60}=33$