In India, electricity is supplied for domestic use at 220V. It is supplied at 110 V in USA. If the resistance of a 60 W bulb for use in India is R , then resistance of a 60 W bulb for use in USA will be

Options

A. R
B. 2R
C. R/2
D. R/4

Answer

D

Explanation

Given : Supply voltage in india
`(V_(1)) = 220, `
V : supply voltage in USA
`(V_(2)) = 110 V ` and
Resistance of 60 w bulb in India
`(R_(1)) = R `
We know that power of the bulb
`(P) = (V_(2))/(R) or R prop V_(2)`
`:.(R_(1))/(R_(2)) = ((V_(1))/(V_(2)))^(2) = ((220)/(110))^(2) = 4 `
(or) `R_(2) = (R_(1))/(4) = (R)/(4)`