In an a.c. circuit voltage v and current i are given by v = 100 sin 100 t volts,
i = 100 sin {100 t + π/3} mA. The power dissipated in the circuit is
Answer & explanation
Correct answer: option 1
$P = V_{rms}I_{rms} cos\phi = \frac{100V}{\sqrt 2} \times \frac{100\times 10^{-3}}{\sqrt 2} \times cos\frac{\pi}{3} = 2.5W$