Alternating Current Ques 42
42. In an a.c circuit the e.m.f. $(e)$ and the current $(i)$ at any instant are given respectively by
$e=E_0 \sin \omega t$
$i=I_0 \sin (\omega t-\phi)$
The average power in the circuit over one cycle of a.c. is
(a) $\frac{E_0 I_0}{2}$
(b) $\frac{E_0 I_0}{2} \sin f$
(c) $\frac{E_0 I_0}{2} \cos f$
(d) $E_0 I_0$
Show Answer
Answer:
Correct Answer: 42.(c)
Solution:
- (c) The average power in the circuit over one cycle of a.c. is given by
$P _{av}=e _{rms} \times i _{rms} \times \cos \phi$
$=\frac{E_0}{\sqrt{2}} \times \frac{I_0}{\sqrt{2}} \times \cos \phi=\frac{E_0 I_0}{2} \cos \phi$
BETA
