Q192 / 200 · Manipal (MET) 2012 · Physics
A 220 V main supply is connected to a resistance of $100 \mathrm{k} \Omega$. The effective current is
- Correct answerA2.2 mA
- B$2.2 \sqrt{2} \mathrm{~mA}$
- C$\frac{2.2}{\sqrt{2}} \mathrm{~mA}$
- DNone of these
Solution
Effective current is the rms value. Here, 220 V is the labelled value of AC which is also the rms value. Hence,
$\begin{aligned}
& I_{\mathrm{rms}}=\frac{E_{\mathrm{rms}}}{R} \\
& I_{\mathrm{rms}}=\frac{220}{100 \times 10^3} \\
& I_{\mathrm{rms}}=2.2 \mathrm{~mA}
\end{aligned}$
Hence, the correct answer is option: 'A'.