Question

The capacity of a condenser is $4 \times 10^{-6} F$ and its potential is $100\, V$. The energy released on discharging it fully will be

• A. 0.04 J
• B. 0.02 J
• C. 0.025 J
• D. 0.05 J

Answer 1

Answer: (B)

0.02 J

Answer 2

Energy released on discharging the capacitor fully is given by
$E=\frac{1}{2} C V^{2}$
Given, $C=4 \times 10^{-6} F,\,\, V=100$ volt
$\therefore E=\frac{1}{2} \times 4 \times 10^{-6} \times(100)^{2}$
$\Rightarrow E=2 \times 10^{-2}$
$=0.02\, J$