Q. A parallel plate condenser has a uniform electric field E (V/m) in the space between the plates. If the distance between the plates is d (m) and area of each plate is A (m²) the energy (joules) stored in the condenser is
A) (1/2)ε₀E²Ad
B) E²Ad/ε₀
C) (1/2)ε₀E²
D) ε₀EAd
Explanation
[Solution from source] The energy density in the field is (1/2)ε₀E² and the field fills a volume Ad, so U = (1/2)ε₀E²Ad. The expression (1/2)ε₀E² alone is just the energy per unit volume, not the total energy. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.