The instantaneous current and voltage of an a.c. circuit are given by $i=10\sin 314t$ A and $v=50\sin\!\left(314t+\frac{\pi}{2}\right)$ V. What is the power dissipation in the circuit?

CBSE Class 12 · 2008 · All India · Alternating CurrentVery Short Answer

The instantaneous current and voltage of an a.c. circuit are given by

i = 10 sin 314 t

A and

v = 50 sin (314 t + \frac{π}{2})

V. What is the power dissipation in the circuit?

Answer: $P = 0$ (zero).

The phase difference between voltage and current is

ϕ = \frac{π}{2}

P_{a v} = V_{r m s} I_{r m s} cos \frac{π}{2} = 0

The circuit is purely reactive, so it is wattless.

P_{a v} = 0

CBSE Class 12 Board · 2008 · All India · Subjective