Alternating Current - Result Question 8

8. In an A.C. circuit with voltage $V$ and current $I$ the power dissipated is

[1997]

(a) dependent on the phase between V and I

(b) $\frac{1}{\sqrt{2}} VI$

(c) $\frac{1}{2} VI$

(d) VI

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Answer:

Correct Answer: 8. (a)

Solution:

  1. (a) Power dissipated $=E _{\text{rms }} \cdot I _{\text{rms }}$

$=(E _{rms})(I _{rms}) \cos \theta$

Hence, power dissipated depends upon phase difference.