If `u_E,u_m` are the energy density of e.m. wave due to electric and magnetic field vectors, `E_(rms) , B_(rms)` are the rms value of electric and magnetic field vectors in e.m. wave, then the total energy density of a sinusoidaly e.m wave is

Options

A. `u_E`
B. `u_E+u_m`
C. `1/2in_0E_(rms)^2+(B_(rms)^2)/(2mu_0)`
D. `1/4in_0E_0^2+1/2 (B_0^2)/(2mu_0)`

Answer

(b,c)

Explanation

Total energy of e.m. wave is
`u=u_E+u_B`
`=1/2in_0 E_(rms)^2+ 1/2 (B_(rms)^2)/(mu_0)=1/4in_0 E^2+ 1/4 (B_0^2)/(mu_0)`