Question

If an AC main supply is given to be 220 V. The average emf during a positive half cycle will be

• A. 198 V
• B. 220 V
• C. 240 V
• D. $220\sqrt{2}V$

Answer 1

The correct option is A 198 V

$E_{rms}=220V$
$\therefore E_{rms}=\frac{{\epsilon }_0}{\sqrt{2}}\Rightarrow {\epsilon }_2=\sqrt{2}{E}_{rms}$
Average e.m.f over half cycle
$=\frac{2}{\pi }{\epsilon }_0=0.637\times 1.41\times 220=198.15V$