Question

An electric bulb is rated 220 volt and 100 watt, Power consumed by it when operated on 110 volt is :

• A. 50 W
• B. 85 W
• C. 90 W
• D. 45 W

Answer 1

The correct option is A 50 W

Answer is A.
The power dissipated by an electric bulb is given as P = VI.
In this case, Power P = 100 W and Voltage V = 220 V.
So, current I is I = P/V = 100/220 = 0.45 A.
When the supplied voltage is 110 V, the power consumed will be P=VI = 110 * 0.45 = 50 W.
Hence, the power consumed when operated at 110 V is 50 W.