An alternating current is given by $I=100 \sin (50 \pi t)$. How many times will the current become zero in…
An alternating current is given by $I=100 \sin (50 \pi t)$. How many times will the current become zero in one second?
50 times
25 times
40 times
100 times
Solution
Current is given by, $\mathrm{I}=\mathrm{I}_0 \sin \omega t$...(i)
Given, $I=100 \sin (50 \pi t)$
Comparing with (i),
$\omega=50 \pi$
$\therefore \quad 2 \pi \mathrm{f}=50 \pi$
$\therefore \quad \mathrm{f}=25 \mathrm{~Hz} \Rightarrow 25$ cycles per second Current becomes zero twice in one cycle
$\therefore \quad$ Current becomes zero, $25 \times 2=50$ times