Question

An electric bulb is rated 220V and 100W. When it is operated on 110V, then the power consumed will be ?

Answer 1

Hi friend ,

P = V^2/R  
If V = 220 V we have

100 W = 220^2/R
R = 220^2/100 Ω = 484 Ω. This is the resistance of the bulb.

When V = 110 V, power consumed =  V^2/R = 110^2/484 = 25 W.

So, 25 W power is consumed when it is operated on 110 V.

Answer 2

Answer:

When an  electric blub is rated 220v and 100 w is operated on 110 v, then the power consumed will be 25 W.

Explanation:

Equation P =$V^{2}$/R

from question V = 220 v

100 W = $220^{2}$/R

R = $220^{2}$/100 Ω = 484 Ω.

484 Ω. is the  resistance of the bulb.

When V = 110 V

power consumed = $V^{2}$/R

                               = $110^{2}$/484 = 25 W.

So, 25 W power is consumed when it is operated on 110 V