Question

During the propagation of electromagnetic waves in a medium,

• A. electric energy density is double of the magnetic energy density
• B. electric energy density is half of the magnetic energy density
• C. electric energy density is equal to the magnetic energy density
• D. Both electric and magnetic energy densities are zero

Answer 1

Answer: (C)

electric energy density is equal to the magnetic energy density

Answer 2

Energy is equally divided between the electric and magnetic fields. The Electric energy densityis equivalent to the magnetic energy density.

Here, uE= ½ ϵ0E2

uB=B2/2μ0

Also, E=cB and c=1/√μ0ϵ0

Therefore, we get uE = ½ ϵ0E2 = ½ ϵ0(cB)2

=½ ϵ0$1 \over \mu_o \epsilon_o$B2

uE= uB

So, the correct answer is C) During the propagation of electromagnetic wavesin a medium, electric energy density is equal to the magnetic energy density.