In the transmission of a.c. power through transmission lines, when the voltage is stepped up n times, the power loss in transmission ……….

Options

A. increases n times
B. decreases n times
C. increases `n^2` times
D. decreases `n^2` times

Answer

D

Explanation

Average power loss `P=I^2R`
but `I=V/Z`
`therefore P=V^2/Z^2R`
If the voltage is stepped up n times then, we get,
`P_1=n^2(V^2/Z^2)R`
`therefore P_1/P=n^2`