An Electric Bulb is rated 220V and 100W. When it is Operated on 110V, what will be the Power Consumed?

Answer: Let us assume the power as P. It is the rate at which the electrical circuit transfers energy per second.

Formula of power: P = IV

Or, P = I. IR (using Ohm’s Law)

Therefore, P = R. I²

or, P = V²/R … (i)

Here, V is the circuit’s potential difference while I stands for the amount of current.

R = V²/P (from equation i)

Therefore resistance is 220² / 100 = 484 ohms.

Similarly for 110 V electric bulb, power consumed will be = V²/R or, 110² /484 W

Therefore consumed power will be 25 W.