Question

A $110V$ $d.c$. heater is used on an $a.c$. source, such that the heat produced is same as it produces when connected to $110V$ $dc$ in same time-intervals. What would be the r.m.s. value of the alternating voltage?

• A. $110V$
• B. $220V$
• C. $330V$
• D. $440V$

Answer 1

The correct option is A $110V$

For same time interval same heat is produced.

Therefore, power in both $DC$ and $AC$ is also same.

$\frac{V_{DC}^2}{R}=\frac{V_{rms}^2}{R}=P$

$V_{rms}=V_{DC}=110V$