An electromagnetic (em-) wave in free space has an electric field described by E (r, t) = x (50 cos (w t-k z)]} V/m, with v = = 10⁹ Hz. i) Find the average power passing through a circular area of diameter 5 m in the plane where z = 5m. ii) Determine the average momentum density of this em-wave. iii) Calculate the radiation pressure of this em-wave when it falls on a perfect conductor. "II'

An electromagnetic (em-) wave in free space has an electric field described by E (r, t) = x (50 cos (w t-k z)]} V/m, with v = = 10⁹ Hz. i) Find the average power passing through a circular area of diameter 5 m in the plane where z = 5m. ii) Determine the average momentum density of this em-wave. iii) Calculate the radiation pressure of this em-wave when it falls on a perfect conductor. "II'