Question

A sinusoidal alternating current of 25Hz frequency has its maximum value of 100A.How long will it take for the current to attain values of 20A starting from zero value?​

Answer 1

Answer:

Alternating current   i=iosinwt

where  w=2πf=2π×50=100 π

For  i=irms=2io

We get   2io=iosinwt

Or   sinwt=21

Or   wt=4π

Or    100π×t=4π

We get   t=4001 seconds