Question

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

(a) Increase n times

(b) Decrease n times

(c) Increase n2 times

(d) Decrease n2 times

Answer 1

The correct option (d) Decrease n2 times

Explanation:

If power transmitted is P, resistance of transmission line is r, current through line is I = (P/V) then

Power loss = I2r = (P/V)2r. As P and r is always constant,

Power loss ∝ (1/V2) hence is V increases n times then loss decreases by n2 times.