Question

A bulb of 100W-200V is connected to a 160 V supply. Find the power consumed.

• A. 25 W
• B. 64 W
• C. 45 W
• D. 20 W

Answer 1

The correct option is B 64 W

Given that when a bulb is connected to 200V it consumes 100W power.

Power is given by -

$P=VI$

$100=200\times II=0.5A$

Resistance of bulb -

$R=\frac{V}{I}=\frac{200}{0.5}=400\Omega$

power when connected to 160V source -

$P^{\prime }=VI=\frac{V^2}{R}=\frac{160\times 160}{400}=64W$