The voltage of an a.c.supply varies with time (t) as V=120 sin 100 πt cos 100 πt the maximum voltage and frequency are respectively

Options

(a) 120 V and 100 Hz
(b) 120√2 v and 100 Hz
(c) 60 V and 200 Hz
(d) 60 V and 100 Hz

Correct Answer:

60 V and 100 Hz

Explanation:

V = 120 sin 100 πt cos 100 πt

= 60 × 2 sin 100 πt cos 100 πt

= 60 × sin 200 πt

V(max) = 60 V

ω = 200 π

⇒ 2πf = 200 π

⇒ f = 100 Hz

⇒ 60 V and 100 Hz