Question

The rms voltage of a domestic electricity supply is $220\text{V}$. Electrical appliances, connected to this supply, should be designed to withstand a maximum voltage of

• A. $220\text{V}$
• B. $311\text{V}$
• C. $350\text{V}$
• D. $440\text{V}$

Answer 1

The correct option is B $311\text{V}$

The instantaneous voltage, in an AC circuit, varies with time.

For the safety of any appliance, it should be designed to withstand the peak value of voltage.

Here, $220\text{V}$ is the rms value of voltage.

Therefore, peak value of voltage,

$V_0=V_{rms}\times \sqrt{2}$

$\Rightarrow V_0=220\times \sqrt{2}\approx 311\text{V}$

Hence, option $\left(B\right)$ is the correct answer.