Question

A group of electric lamps having a total power rating of `1000` watt is supplied by an `AC` voltage `E=200sin(310t+60^(@))`. Then the r.m.s value of the circuit current is
A. `10` amp
B. `10sqrt(2)`
C. `20` amp
D. `20sqrt(2)` amp

Answer 1

Correct Answer - B
Power `=E_(0)I_(0) cos theta`
or `1000=(2000xxI_(0)//2)cos 60^(@)`
Solving, we get: `I_(0)=20` amp
`:. I_(rms)=20/(sqrt(2))=10sqrt(2)` amp