# Science: Light Energy: Reflection of Light and Laws of Refraction (For CBSE, ICSE, IAS, NET, NRA 2022)

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## Reflection of Light

The bending of light when it travels from one medium to another is called refraction of light. Some objects having smooth and shiny surface reflect better than others. A smooth shining surface, which reflects most of the light incident on it, is called a mirror.

## Laws of Refraction

### First Law

Incident ray reflected ray and the normal at the point of incidence, all lie in the same plane.

### Second Law

• The angle of incidence is equal to the angle of reflection i.e.. ,
• During reflection, there is no change in speed, frequency and wavelength of light.
• Reflection of light may be classified as regular reflection and diffused reflection. When the ray of light passes through rarer medium to denser medium, the refracted bends towards the normal and when it travels from denser to rare medium it bends away from the normal.

## Causes of Refraction of Light

The refraction of light is due to the change in the speed of light when it travels from one medium to another medium. The speed of light in air medium is . however, it decreases in denser medium . the speed of the light in glass is .

## Types of Reflection

1. Regular reflection When reflecting surface is very smooth and the rays of light falling on it are reflected straight off it, then it is called regular reflection.

### 2 Diffused Reflection

When the reflection of light takes place from rough surface the light is reflected off in all directions is called diffused reflection.

### Spherical Mirror

A spherical mirror is a section of a hollow sphere whose inner or outer surface is polished. Thus, there are mainly two types of spherical mirrors

• convex mirror and
• concave mirror

#### Convex Mirror

It is a mirror in which the reflection takes place from the bulging surface (i.e.. inner side is painted, and reflected surface is polished to make the surface smooth .

#### Concave Mirror

It is a mirror in which the reflection takes place from the cave side surface (i.e.. outer side is painted and the inner or cave side surface is polished to make the reflected surface smooth.

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