Question

A heater of rating of 50 W – 200 V is connected with source voltage of 100 V. Power consumed by heater is

(1) 100 W 

(2) 25 W 

(3) 50 W 

(4) 12.5 W

Answer 1

Correct Option is (4) 12.5 W

R = \(\frac{V^2_r}{P_r}= \frac{200\times200}{50}=800Ω\)

P = \(\frac{V^2}{R}=\frac{100\times100}{800}=12.5 \) W