Describe an activity to show that the incident ray, the reflected ray, normal, the point of incidence lie in the same plane.

Explanation

Materials required : White sheet of paper, a drawing board, drawing pins, a comb.
Procedure :
(i) A white sheet of paper on a drawing board is fixed.
(ii) A strip of plane mirror is taken and placed in the path of light ray.
(iii) The ray of light will be reflected.
(iv) Angle of incidence and angle of reflection on the sheet of paper is drawn.
(v) The incident and reflected rays along the paper is observed.
(vi) Now the sheet of paper is bent a little at the position of the reflected ray.
(vii) Keeping the incident ray and the normal in the plane of the drawing board, the reflected ray is tried to be seen now.
The paper is put back and observed again and the activity is repeated for different angles of incidence.
Observation : Firstly, when the paper is bent, then incident ray and normal are found to be on the plane of the paper.
When paper is placed on the drawing board again, then one can see that incident ray, reflected ray and the normal at the point of incidence all lie in the same plane.