Electro Magnetic Induction And Alternating Currents Question 78
Question: In an ac circuit, V and I are given by V = 100 sin (100 t) volts, $ I=100\sin ,( 100t+\frac{\pi }{3} ),mA $ . The power dissipated in circuit is [MP PET 1989; RPET 1999; MP PMT 1999, 2002]
Options:
A) 104 watt
B) 10 watt
C) 2.5 watt
D) 5 watt
Show Answer
Answer:
Correct Answer: C
Solution:
$ P={V_{r.m.s.}}\times {i_{r.m.s.}}\times \cos \varphi $
$ =\frac{100}{\sqrt{2}}\times \frac{100\times {{10}^{-3}}}{\sqrt{2}}\times \cos \frac{\pi }{3} $
$ =\frac{10^{4}\times {{10}^{-3}}}{2}\times \frac{1}{2}=\frac{10}{4}=2.5\ watt $
