Question: What is the energy stored in a capacitor of 20 µF charged to 10 V?

Options:

1. 0.1 J
2. 0.2 J
3. 0.05 J
4. 0.15 J

Correct Answer: 0.2 J

Solution:

Energy U = 0.5 * C * V² = 0.5 * 20 x 10^-6 F * (10 V)² = 0.1 J.