Consider an electromagnetic plane wave travelling in vacuum in the direction of the vector n = (1,1,1) (in Cartesian coordinates). The polarisation of the wave is in the x-y plane. Assume that at t = 0 the electric field strength is zero at the origin. The frequency of the wave is w. a) What are the electric and magnetic field expressions for the wave? b) Suppose that a perfectly reflecting plane surface with its normal along n is placed in the path of the wave. What is the pressure exerted by the wave on this surface?