Capacitors: Practice Problem & Solution

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Capacitors. Understanding the underlying formula is key to arriving at the correct answer below:

Energy density $u = \frac{1}{2} \varepsilon_{0} E^{2}$. Total energy $U = u \times \text{volume} = \frac{1}{2} \varepsilon_{0} E^{2} A d$.