Question

An AC voltage source, $V=200\sqrt{2}\sin 100t$, is connected across a circuit containing an AC ammeter and capacitor of capacity $1\mu F$. Reading of the ammeter is:

• A. $10\text{mA}$
• B. $20\text{mA}$
• C. $40\text{mA}$
• D. $80\text{mA}$

Answer 1

The correct option is B $20\text{mA}$

For the given circuit,
$X_C=\frac{1}{\omega C}=\frac{1}{100\times 1\times {10}^{-6}}={10}^4\Omega$

An AC ammeter always reads the rms value of current.

So, $I_{rms}=\frac{V_{rms}}{R}=\frac{\left(\frac{200\sqrt{2}}{\sqrt{2}}\right)}{{10}^4}=\frac{200}{{10}^4}=20\text{mA}$

Hence, $\left(B\right)$ is the correct answer.