The average value of electric energy density in an electromagnetic wave is. [where E ₀ is peak value]

Step-by-step solution

The energy density in EM wave is u = 1 2 _ o E ^2= 1 2 _ o E ₀^2 ^2( t - kx ) Average energy density, u = 1 2 ₀ E ₀^2 ^2( t - kx ) = ( 1 2 ₀ E ₀^2 ) 1 2 = 1 4 ₀ E ₀^2