Question

If the angle between the plane mirror and the incident ray is 40 degree.What are the angles of incidence and reflection?​

Answer 1

Here, we are given that the angle between the plane mirror and the incident ray is 40°. We have to find the angle of reflection and the angle of incidence.

Let,

• AB be the surface of the plane mirror.
• CO is the normal.
• MO is the incident ray.
• NO is the reflected ray.
• O is the point of incidence.

We are given that the measure of ∠AOM is 40°.

We know that the normal is the perpendicular on the point of incidence. Measure of perpendicular angle is 90°. So,

Finding angle of incidence :

$\longmapsto$ ∠AOM+∠COM=90

• »› ∠AOM is 35°.
• »› ∠COM is angle of incidence.

$\longmapsto$ 40° + ∠i =90

$\longmapsto$ ∠i = 90° - 40°

$\longrightarrow \sf \red{ \angle i = 50^\circ}$

Therefore,

• Measure of angle of incidence is 50°.

Finding measure of angle of reflection :

As we know that :

»› According to the laws of reflection, angle of incidence and angle of reflection are always equal.

So,

$\longmapsto$ ∠i = ∠r

$\longrightarrow \sf \red {50^\circ = \angle r }$

Therefore,

• Measure of angle of reflection is 50°.

More Information :

Reflection of light :

• Reflection is the bouncing back of light when a ray or beam of ray of light strikes on the surface.
• There are two types of reflection ::

1. Regular reflection
2. Diffused reflection

Laws of reflection :

• First law of reflection states that the incident ray, the reflected ray and the normal lie on the same plane.

• Second law of reflection states that the angle of incidence and the angle of reflection are always equal.

Answer 2

Explanation:

Here, we are given that the angle between the plane mirror and the incident ray is 40°. We have to find the angle of reflection and the angle of incidence.

Let,

AB be the surface of the plane mirror.

CO is the normal.

MO is the incident ray.

NO is the reflected ray.

O is the point of incidence.

We are given that the measure of ∠AOM is 40°.

We know that the normal is the perpendicular on the point of incidence. Measure of perpendicular angle is 90°. So,

Finding angle of incidence :

\longmapsto⟼ ∠AOM+∠COM=90

»› ∠AOM is 35°.

»› ∠COM is angle of incidence.

\longmapsto⟼ 40° + ∠i =90

\longmapsto⟼ ∠i = 90° - 40°

\longrightarrow \sf \red{ \angle i = 50^\circ}⟶∠i=50

∘

Therefore,

Measure of angle of incidence is 50°.

Finding measure of angle of reflection :

As we know that :

»› According to the laws of reflection, angle of incidence and angle of reflection are always equal.

So,

\longmapsto⟼ ∠i = ∠r

\longrightarrow \sf \red {50^\circ = \angle r }⟶50

∘

=∠r

Therefore,

Measure of angle of reflection is 50°.

More Information :

Reflection of light :

Reflection is the bouncing back of light when a ray or beam of ray of light strikes on the surface.

There are two types of reflection ::

Regular reflection

Diffused reflection

Laws of reflection :

First law of reflection states that the incident ray, the reflected ray and the normal lie on the same plane.

Second law of reflection states that the angle of incidence and the angle of reflection are always equal.