Question

If an ac main supply is given to be 220 V. What would be the average e.m.f. during a positive half cycle(a) 198V(b) 386V
(c) 256V(d) None of these

Answer 1

answer : option (a) 198V

explanation : a/c to question, main supply of an ac circuit is given to be 220V
so, $V_{rms}=220V$

we know, $V_{peak}=\sqrt{2}V_{rms}$

so, $V_{peak}=220\sqrt{2}$.....(1)

use formula, $V_{av}=\frac{2}{\pi}V_{peak}$
or, $V_{av}=\frac{2}{\pi}220\sqrt{2}$

or, $V_{av}=\frac{440\sqrt{2}}{\pi}$

hence, $V_{av}\approx198V$