Question

The current and voltage in AC circuit are given by
$ I=5\sin \left( 100t-\frac{\pi }{2} \right)A $ and
$ V=200\sin (100t) $ volt. The power dissipated in the circuit will be

• A. 20 W
• B. 40 W
• C. 1000 W
• D. zero

Answer 1

Answer: (D)

$ P={{E}_{rms}}\times {{i}_{rms}}\times \cos \phi $
$ \phi =\frac{\pi }{2} $
$ \cos \phi =0 $
$ P={{E}_{rms}}\times {{i}_{rms}}\times (0)=0 $