Question

A generator produces a time varying voltage given by `V=240 sin 120 t,` where `t` is in second. The rms voltage and frequency are
A. 60 Hz and 240 V
B. 19 Hz and 120 V
C. 19 Hz and 170 V
D. 754 Hz and 170 V

Answer 1

Correct Answer - C
`e=240sin120t`,
comparing this equation with
`e=e_(0)sinomegat,` we have
`e_(0)=240V and omega=120rad//sec`.
`therefore f=(120)/(2pi)~~19Hz`
`e_(rms)=(e_(0))/(sqrt(2))=(240)/(1.414)~~170V`