When a ray of light travelling in one medium enters another medium,it bends away from its path.
This bending of waves from their path is called Refraction.
Refraction occurs due to change in speed of light in the other medium.
Laws Of Refraction:
There are two main 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.When a ray of light passes from one particular medium to another,the ratio of the sine of angle of incidence i to sine of angle of refraction r is a constant.
This constant ratio is called the Refractive Index of the second medium with respect to (w.r.t) the first and is denoted by letter n
n = sin I / sin r
The refractive Indext can also be calculated by dividing the speed of light in vacuu by the speed of light in that medium.
As the speed of light in vacuum is almost equal to speed of light in air,we can use speed of light in air instead of speed in vacuum.
Refractive Indices of Various substances:
Medium Refractive Index
Air 1.003
Vacuum 1.000
Water 1.33
Ice 1.30
Diamond 2.42
Glycerine 1.47
Alcohol 1.36
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