Question

If the rms current in a 50 Hz AC circuit is 5 A, the value of the current 1/300 s after its value becomes zero is ______.

Options

• 5\[\sqrt 2\] A

• 5\[\sqrt {\frac {3}{2}}\]A

• \[\frac {5}{6}\]A

• \[\frac {5}{\sqrt 2}\]A

Answer 1

If the rms current in a 50 Hz AC circuit is 5 A, the value of the current 1/300 s after its value becomes zero is 5\[\sqrt {\frac {3}{2}}\]A.

Explanation:

Here, I_rms = 5 A, f = 50 Hz and t = \[\frac {1}{300}\]s

I₀ = Peak value = \[\sqrt 2\]I_rms = \[\sqrt 2\] × 5 = 5\[\sqrt 2\]A

Now, 1 = I₀ sin ωt = 5\[\sqrt 2\] sin 2πft = 5\[\sqrt 2\]sin 2π × 50 × \[\frac {1}{300}\] = 5\[\sqrt {\frac {3}{2}}\]A