Power consumed in a bulb of 1000W and 220V when connected to 110 V mains = .........

Options

A. 750 W
B. 500 W
C. 250 W
D. 1000 W

Answer

C

Explanation

250 W
`P_(1) = (V_(1)^(2))/(R) and P_(2) = (V_(2)^(2))/(R)`
`therefore (P_(2))/(P_(1)) = ((V_(2))/(V_(1)))^(2)`
`therefore P_(2) = P_(1) xx ((V_(2))/(V_(1)))^(2) = 1000 xx ((110)/(220))^(2) = (1000)/(4)`
`therefore P_(2) = 250 W `