Question

The angle which the __________________makes with the normal at the point of incidence is called angle of incidence.

Answer 1

Hint: This question refers to optics phenomenon reflection or refraction because in both the phenomenon angle of incidence and angle of reflection is used. There are three rays in both the phenomenon as incident ray; reflected ray and normal ray and all have the same point of intersection called point of incidence.

Complete step-by-step solution: -
When obliquely light falls on any surface and after striking from the surface it bounces back in the same medium then this is called the phenomenon of reflection. The surface through which it strikes is called the reflecting surface. The reflecting surface is a mirror, it has two types: - plane mirror and spherical mirror. Here in the given diagram we use a plane mirror.
A ray coming towards the reflecting surface is called incident ray and after reflection the ray bounces back is called the reflected ray. A perpendicular ray passing through that reflecting surface is called normal ray. The incident ray makes angle i from the normal ray which is called the incident angle and the reflected ray makes angle r with the normal called the reflected ray.
According to Laws of reflection:-
The incident ray, the refracted ray and normal ray all lie at the same point of incidence in the same plane.
The angle of incidence is always equal to the angle of reflection.
This incident angle is also connected to the optics phenomenon refraction but this angle of incidence is the same whether we study in reflection or refraction, since these two phenomenons are different but angle of incidence is same for both the cases. In refraction light transmits to another medium while in reflection it is in the same medium.
Here we can conclude that, the angle which the incident ray makes with the normal at the point of incidence is called angle of incidence in both the phenomena.

Note: In refraction, when light bounces back in the same medium after refraction then its velocity, wavelength and frequency of incident ray and reflected ray are same. While in refraction, when light bounces in a different medium then its velocity and wavelength will change while its frequency remains the same.