Question

If the angle of incidence is ${80^ \circ }$, what will be the angle of reflection with respect to the normal drawn perpendicular at the point of reflection?
A. ${80^ \circ }$
B. ${100^ \circ }$
C. ${160^ \circ }$
D. ${20^ \circ }$

Answer 1

Hint: We have to understand the phenomenon of reflection in order to get a proper solution. The laws of reflection play an important part to answer this specific question. With the help of a diagram we will understand the phenomenon more clearly.

Complete answer:
Reflection is defined as the natural phenomenon by which a light when it strikes a surface changes its direction of propagation.Reflection is again of mainly two types,
(i) Regular reflection: When a light strikes on a smooth shiny surface then the light after striking bounce back at the same angle at which it strikes.
(ii) Irregular reflection: When a ray of light strikes a rough surface then the reflected angle is not the same as the incident angle.

So, the reflection mentioned here is regular reflection.
The laws of reflection states that-
(i) The angle of reflection is equal to the angle of incidence.
(ii) The reflected ray, the incident ray, the normal all lie on the same plane.
Since, the angle of incidence is ${80^ \circ }$ then the angle of reflection is also ${80^ \circ }$.

So, the correct option is A.

Note: It must be noted that in this question we must consider it as regular reflection. If we consider the reflection type as irregular, then without the value of the inclination of the irregular surface we will not be able to find the reflected angle. Regular surface refers mainly to mirrors. A transparent or translucent object reflects the most amount of light whereas an opaque object reflects less.