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