(a) consider an electromagnetic wave of the form e eolicos(kz - wt)0.8j sin(kz - wt + ¢) _ (i) discuss the effect of the phase d on the state of polarisation of the wave. (ii) for what value(s) of the phase 0 is this wave linearly polarised? (ii we pass that field through a half-wave plate. for the phase value you obtained in (ii), at what relative angle polarisation state into 'horizontal' (0°)? explain your answer. must the axis of this half-wave plate be oriented to turn the (b) (advanced) a sheet of plastic, uniformly 1.5 mm polarizers which are illuminated from the back with 532 nm bright bands appears. how much does the relative difference in the index of refraction in the plastic (nn1) have to vary in order to produce the half-wave plate behaviour needed to create successive dark and bright bands? show all working thick, is viewed between crossed linear light.