The electric field of a plane electromagnetic wave propagating in a non-magnetic dielectric medium with a refractive index of 3 is given by E = 60 (kx - t) j V/m. The average intensity of the electromagnetic wave is:

Step-by-step solution

The amplitude of the electric field is E₀ = 60 V/m. The average intensity of an electromagnetic wave in a medium is given by I = 1 2 v E₀^2 , where is the permittivity of the medium and v is the speed of the wave. For a non-magnetic medium, the refractive index is n = _r , so = n^2 ₀ . The speed of the wave is v = c n . Substituting these into the intensity formula gives: I = 1 2 (n^2 ₀) ( c n ) E₀^2 = 1 2 n ₀ c E₀^2 We know that ₀ c = 1 ₀ c = 1 120 ⁻¹ . Substituting the values n = 3 and E₀ = 60 V/m: I = 1 2 3 1 12