# Law of reflection of light

Definition of reflection

Reflection can be interpreted as an event in which the direction of motion of an object changes due to the object hits a barrier. If you throw a ball on the wall, the ball reflected because the ball hits the wall.

Reflection of light

When light is emitted by the sun or other light sources such as electric lights, light moves from the light source in all directions. When light strikes a barrier such as a book, wall or mirror, light is reflected by that barrier. The direction of the light reflection after strikes a barrier object is different from the direction of motion of the light before it strikes the barrier. It can be said that the reflection of light is an event in which light strikes a barrier so that the direction of light changes; the direction of movement of light after strikes a barrier object is different from the direction of motion of light before strikes a barrier.

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The law of reflection of light

The law of reflection of light is a physics law that explains the event of reflection of light. You can prove this law by conducting a light reflection experiment. Following is the statement of the law of reflection of light:

1. Incident light rays (p), reflected light rays (q) and the normal to the surface (N) lie in the same plane. p = Incident light rays, q = reflected light rays, i = angle of incidence, r = angle of reflection, N = normal to surface

Incident light rays

Incident light rays are beams of light that move towards a barrier object. If the barrier object is a book, the incident light rays are beams of light moving towards the book. If a barrier object is a mirror, the incident light rays are beams of light that move toward the mirror.

Reflected light rays

Reflected light rays are beams of light that move away from the barrier object after the strike the barrier.

Normal to surface

The normal line is an imaginary line perpendicular to the surface of the barrier object hit by a beam of light. If the barrier object is a mirror, the normal line is an imaginary line perpendicular to the mirror surface through which the beam of light passes.

Plane

Plane are flat surfaces and have certain limits. The plane also can be interpreted as the surface area. Observe the figure. If you put a sheet of paper vertically so that it coincides with the incident light rays, reflected light rays and the normal line then the surface of the paper lies in a flat plane with the incident light rays, reflected light rays and normal line. Likewise with Figure 2. If you place a piece of paper vertically so that it coincides with the incident light rays, reflected light rays and the normal line then the surface of the paper lies in a flat plane with the incident light rays, reflected light rays and normal line.

2. The angle of incidence is the same as the angle of reflection

If the angle of incidence is 30o, the angle of reflection is 30o. If the angle of incidence is 90o (the direction of motion of the ray comes perpendicular to the surface of the object), the angle of reflection is 90o (the direction of the reflected light is perpendicular to the surface of the object but opposite and coincides with the direction of the incident light rays). 