Question

An AC source is rated $220\text{V},50\text{Hz}$. The average voltage, is calculated in a time interval of $0.01\text{s}$. It

• A. must be zero
• B. is never zero
• C. may be zero
• D. must be infinite

Answer 1

The correct option is B is never zero

Given:
$f=50\text{Hz}$

$\therefore$ Time period, $T=\frac{1}{f}=\frac{1}{50}=0.02\text{s}$

The sum of the instantaneous value of voltage over one complete cycle of AC source is zero.

As the time interval in the question $\left(0.01\text{s}\right)$ is not an integral multiple of the time period $\text{T}=0.02\text{s}$, so the average value will never be zero.

Hence, $\left(\text{B}\right)$ is the correct answer.