Question

The energy associated with electric field is E and with magnetic field is B for an electromagnetic wave in free space is given by( \(∈_0\)-permittivity of free space \(μ_0\)-permeability of free space) 

• A. \(U_E=\frac{E^2}{2∈_0},U_B=\frac{μ_0B^2}{2}\)
• B. \(U_E=\frac{∈E^2}{2},U_B=\frac{μ_0B^2}{2}\)
• C. \(U_E=\frac{E^2}{2∈_0},U_B=\frac{B^2}{2μ_0}\)
• D. \(U_E=\frac{∈_0E^2}{2},U_B=\frac{B^2}{2μ_0}\)

Answer 1

The Correct Option is D

By theory of electromagnetic waves: \[ U_E = \frac{1}{2} \epsilon_0 E^2 \quad \text{and} \quad U_B = \frac{1}{2} \mu_0 B^2 \]