The process of sending back light rays which fall on the surface of an object, is called reflection of light. A plane mirror reflects almost all the light which falls on it.

Reflection of Light

Definition: Reflection of light is the process by which light waves bounce off a surface and change direction. When light strikes a surface, it may be absorbed, transmitted, or reflected.

Key Points:
1. Reflection occurs when light waves encounter a boundary between two different mediums, such as air and glass, or air and water.
2. The angle of incidence, or the angle at which the light waves strike the surface, is equal to the angle of reflection, or the angle at which the light waves bounce off the surface.
3. The law of reflection states that the incident ray, the reflected ray, and the normal (a line perpendicular to the surface) all lie in the same plane.
4. The incident ray is the incoming ray of light, the reflected ray is the ray that bounces off the surface, and the normal is the line perpendicular to the surface at the point of incidence.
5. The angle of incidence and the angle of reflection are measured with respect to the normal.
6. The angle of incidence can vary from 0° (when the light ray is perpendicular to the surface) to 90° (when the light ray is parallel to the surface).
7. The angle of reflection is always equal to the angle of incidence.
8. The reflected light can form an image, and the nature of the reflection (regular or diffuse) depends on the smoothness of the surface.
9. Regular reflection occurs when the surface is smooth and the reflected rays are parallel, resulting in a clear image.
10. Diffuse reflection occurs when the surface is rough, causing the reflected rays to scatter in different directions, resulting in a blurred or scattered image.

Examples:
1. Mirrors reflect light in a regular manner, allowing us to see clear images.
2. Shiny metals, such as polished aluminum, also reflect light in a regular manner.
3. Rough surfaces, like paper or a wall, reflect light in a diffuse manner, scattering the light in different directions.

Applications:
1. Reflection of light is the basis of how we see objects. When light reflects off an object and into our eyes, we perceive the object.
2. Mirrors are used in various applications, such as in telescopes, cameras, and bathrooms.
3. Reflectors on bicycles, cars, and road signs use reflection to enhance visibility at night.
4. Reflective materials are used in clothing and accessories for safety purposes, making the wearer more visible in low light conditions.

In conclusion, reflection of light is the process by which light waves bounce off a surface and change direction. It follows the law of reflection, where the angle of incidence is equal to the angle of reflection. The nature of reflection can be regular or diffuse, depending on the smoothness of the surface. Reflection of light is essential for our vision and has various practical applications in everyday life.