The energy density associated with electric field `vecE` and magnetic field `vecB` of an electromagnetic wave in the free space is given by (`in_0` -permittivity of free space,`mu_0` - permeability of free space)

Options

A. `U_E=(in_0E^2)/2`,`U_B=(mu_0B^2)/2`
B. `U_E=(in_0E^2)/2`,`U_B=(B^2)/(2mu_0)`
C. `U_E=(E^2)/(2in_0)`,`U_B=(mu_0B^2)/(2)`
D. `U_E=(E^2)/(2in_0)`,`U_B=(B^2)/(2mu_0)`