Question

If the angle of incidence of a ray of light on a plane mirror is 40° , the deviation of the incident ray after reflection is​

Answer 1

When a ray of light is incident on a plane mirror, the angle of incidence is equal to the angle of reflection. This is known as the law of reflection.
In your case, the angle of incidence is given as 40°. Since the angle of incidence and angle of reflection are equal, the deviation of the incident ray after reflection would be twice the angle of incidence.
Therefore, the deviation of the incident ray after reflection in this case would be 2 * 40° = 80°.

Answer 2

When a ray of light is incident on a plane mirror, the angle of incidence is equal to the angle of reflection. This is known as the law of reflection.

In your case, the angle of incidence is given as 40°. Since the angle of incidence and angle of reflection are equal, the deviation of the incident ray after reflection would be twice the angle of incidence.

Therefore, the deviation of the incident ray after reflection in this case would be 2 * 40° = 80°.