The peak to peak voltage of a 220 V ac source is approximately

The correct answer is Option (4) → 622 V

The voltage quoted for an ac supply is its rms value, so 220 V is \( V_{\mathrm{rms}} \). The peak value is \( \sqrt{2} \) times the rms value, and the peak-to-peak voltage runs from \( +V_0 \) to \( -V_0 \).

    \( \displaystyle V_0 = \sqrt{2}\,V_{\mathrm{rms}} = 1.414 \times 220\,\mathrm{V} \approx 311\,\mathrm{V} \)

    \( \displaystyle V_{\mathrm{pp}} = 2V_0 = 2 \times 311\,\mathrm{V} \approx 622\,\mathrm{V} \)