Question

an electric bulbe is rated 220 V and 100W. When it is operated on 110V, the power consumed will be:
(a) 100W (b)75W (c) 50W (d) 25W

Answer 1

We know that
power=voltage *current

here
p=100w
v=220v
so current
i=p/v=100/220=10/22a

and voltage =110v
then
power=110*10/22=50w