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# What is meant by refraction of light?

## 1-definition ,

When a ray of light travels through a transparent medium, the light travels in the form of a straight line.
But when light travels from one transparent medium to another transparent medium, the path of the ray (light) at the interface separating the two mediums gets changed.

A ray of light either bends towards the normal or moves away from the normal, this phenomenon of light is called “refraction of light”.
In simple words it can be said that –
When light travels from one medium to another, the path of light gets deflected, this phenomenon is called refraction of light.

## 2-Following are the two laws of refraction –

1. The incident ray, the refracted ray and the normal at the point of incidence all lie in the same plane.
2. The ratio of the sine of the angle of incidence (sin i) and that of the angle of refraction (sin r) for any two mediums remains constant. This fixed ratio is called Snell’s law.
Let a ray of light is incident at an angle i and after refraction its angle of refraction becomes r, then according to Snell’s law

## 3-Refractive Index

The transmission of rays of light through a pair of two mediums For The extent of the change in direction is expressed as the refractive index.

In other words, the ratio of the sine of the angle of incidence to the sine of the angle of refraction for a pair of rays of light is called the refractive index.

### 4-refractive index and speed of light

The value of refractive index shows the relative speed of light in a pair of two mediums. The speed of light is different in different medium. The speed of light in vacuum is 3×108 m/s3×108 m/s, which is maximum and the speed of light in air is slightly less than the speed of light in vacuum.

The speed of light is less in a denser medium than in a rarer medium.

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