Question

An AC voltage is represented by
$e=220\sqrt{2}\cos \left(50\pi \right)t$
How many times will the current become zero in $1s$?

• A. $50$ times
• B. $100$ times
• C. $30$ times
• D. $25$ times

Answer 1

The correct option is A $50$ times

Comparing given equation to standard a.c. equation gives us $2\pi f=50\pi$
so, $f=25$ Hz
In one second there are 25 cycles and in each cycle current becomes zero two times.
so current become zero in 1s for 50 times.