Question

A $220$V main supply is connected to a resistance of $100$k$\Omega$. The effective current is?

• A. $2.2$mA
• B. $2.2\sqrt{2}$mA
• C. $\frac{2.2}{\sqrt{2}}$mA
• D. None of these

Answer 1

Answer: (A)

$2.2$mA

Effective current is the rms value. Here, $220$V is the labelled value of AC which is also the rms value. Hence,
$I_{rms}=\frac{E_{rms}}{R}$
$I_{rms}=\frac{220}{100\times {10}^3}$
$I_{rms}=2.2mA$.