Q. Consider a parallel plate capacitor of area A (of each plate) and separation 'd' between the plates. If $E$ is the electric field and $\epsilon_0$ is the permittivity of free space between the plates, then potential energy stored in the capacitor is
A) $\epsilon_0E^2Ad$
B) $\frac12\epsilon_0E^2Ad$
C) $\frac14\epsilon_0E^2Ad$
D) $\frac34\epsilon_0E^2Ad$
Explanation
[Solution by Dr. Abubacker] Energy density $=\frac12\epsilon_0E^2$ and volume $=Ad$, so $U=\frac12\epsilon_0E^2Ad$. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.