Time taken from zero to maximum for an A.C. voltage of frequency 50Hz will be ......... ms.

Options

A. 5
B. 10
C. 20
D. 50

Answer

A

Explanation

`V=V_m sin omegat`
If `V=V_m` then 1=sin `omega`t
`therefore omegat=pi/2`
`therefore t=(pixxT)/(2xx2pi) [ because omega=(2pi)/T]`
`therefore t=T/4`
`therefore t=1/(50xx4) [ because T=1/f=1/50]`
`therefore t=1/200`
`therefore t=5xx10^(-3)` s
`therefore` t=5 ms