Physics
Answer
The laws of reflection of light can be verified by the following experiment:
- Take a drawing board and a white sheet of paper. Fix the white sheet of paper on the drawing board. Draw a straight line MM1 on the paper.
- On the line MM1 take a point O at its middle and draw a line OA such that ∠MOA is less than 90°. Draw a normal ON on MM1 at point O.
- Take a small plane mirror and place along the line MM1. Use plasticine to fix the mirror on the paper so that it stands upright.
- Fix pins P and Q vertically on the line OA. Set your eye on the other side of the normal ON along the direction as shown in below figure.
- You will see images P', Q' of pins P and Q in the mirror.
- Set your eye in line with the two images P', Q' and fix two more pins R and S on the paper in front of the mirror such that both the pins R and S are in line with P', Q'.
- Remove the mirror and draw small circles around pins P, Q, R and S. Draw a line OB joining the points R and S.
- AO is incident ray, OB is reflected ray and ON is normal at the point of incidence O.
- Using a protractor measure angle of incidence i (∠AON), angle of reflection r (∠BON). We will find two angles are equal.
This experiment verifies the two laws of reflection:
- Angle of incidence = Angle of reflection.
- Incident ray, reflected ray and normal all lie in the same plane of paper which is the second law of reflection.
Related Questions
Draw a diagram to show the reflection of a ray of light by a plane mirror. In the diagram, label the incident ray, the reflected ray, the normal, the angle of incidence and the angle of reflection.
Draw a diagram to show the reflection of a light ray incident normally on a plane mirror.
A ray of light falls normally on a plane mirror. What is the angle of incidence?
State the two laws of reflection of light.