Question

Find the plane of the reflection experimentally for the incident ray which passes through the heads of pins pierced in front of the mirror.

Answer 1

Hint: To perform it experimentally, first, we know about laws of reflection of light. First of all, a reflection of light is defined as the phenomenon of bouncing back of light when an incident on a mirror reflects from that surface. There are two laws of reflection of light:
i) The angle of the incident is equal to the angle of reflection.
ii) The incident ray, the reflected ray, and the normal ray all lie in the same plane.

Complete step by step answer:
Aim: To find the plane of reflection.

Required material: Mirror strip, wooden drawing board, white sheet paper, pins, clamps, scale
and a pencil.

Procedure:
1. Consider a drawing board and fix a white sheet paper on it with clamps.
2. Draw a straight line AB at the center of the paper and a normal line (ON) to AB at the point ‘O.’
3. Draw a straight line PQ, making a certain angle with ON fix two pins at the points P and Q on the paper vertically. PQ line indicates the incident ray.
4. Observe the image P’ of the pin P and Q’ of the pin Q, within the mirror, kept along the line AB.
5. Fix two more pins R and S such that they are within the same line as that of P’ and Q.’ Join R, S, and O. This line indicates the reflected ray.
6. In this, the incident ray passes through the points P and Q touching the paper.
7. The reflected ray is the passing through the points ‘R’ and ‘S,’ and ON is normal.
8. The plane in which the incident ray reflected ray and normal would lie is the plane's reflection.

Note: When we do this experiment, it must be compulsory to have some precautions.
i) The distance between two pins minimum 2 to 5 cm.
ii) Pins are placed in a straight line.
ii) Paper division must be accurate.