Two plane mirrors M1 and M2 are placed so that the angle between their reflecting surfaces is 60∘. A ray of light is incident on M1 at an angle of 30∘ to the normal and, after reflection from M1, strikes M2.
(i) Calculate the angle of incidence on M2.
(ii) Find the angle between the direction of the ray after its second reflection from M2 and the original incident ray.