A narrow beam of monochromatic light is incident on a plane mirror in a laboratory set-up.
a. (i) Define the terms (a) incident ray, (b) reflected ray and (c) normal at the point of incidence.
b. (ii) State the two laws governing reflection of light at a plane surface.
c. (iii) Using a neat, labelled ray diagram and elementary geometry, prove that the angle between the incident ray and the reflected ray is twice the angle of incidence.