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
State the two laws of reflection of light.
A ray of light falls normally on a plane mirror. What is the angle of incidence?
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.