Question

A ray of light is incident on a plane mirror and the angle of reflection is 50. what is the angle between the incident ray and reflected ray?

Answer 1

100°

If a ray of light is incident on a plane mirror and the angle of reflection is 50, then angle between the incident ray and reflected ray will be 100°

We know that, Angle of reflection is opposite to the angle of incident. So here we have to find Reflected ray and incident ray.

=> Angle of incidence= 50°

=> Angle between incident ray and reflected ray + Angle of reflection + angle of reflection  

                   

Angle between incident ray and reflected ray= 50°+50°

Angle of Incident ray = Angle of Reflected ray.

Angle of incidence = <i

Angle of reflection = <r

=> <i + <r

=> 50 + 50

=> 100

Hence, angle between incidence and reflected ray as 100

                                   

As you can see in the attachment. Angle of incident ray is opposite to angle of Reflected ray.

Answer 2

Given,

Angle of reflection =50°
Refer to attachment for diagram.


Now, we know that =>
Angle of incidence = Angle of reflection.

=>Angle of incidence= 50°

(By using laws of Reflection)

So we get =>

Angle of reflection +angle of reflection =Angle between incident ray and reflected ray

=>Angle between incident ray and reflected ray= 50°+50°

=>Angle between incident ray and reflected ray =100°

Hence we get the angle between incidence and reflected ray as 100°.

Remember

Laws of Reflection=>

A)The angle of incidence is equal to the angle of reflection

B) The incident ray, reflected ray and normal all lies on same plane.