Page 3 - Lesson note refraction of light
P. 3
When light rays travel from glass into air or from water into air they bend away from
the normal. The speed of light rays increases while travelling from glass or water into
air.
Laws of refraction of light
1) The incident ray, refracted ray and the normal at the point of incidence, all lie in
the same plane, i.e. the surface/Interface.
2) The ratio of sine of angle of incidence to the sine of angle of refraction is constant
for a given pair of media and for a given colour of light.
Sine of angle of incidence/ sine of angle of refraction = Constant
This constant is called refractive index of medium 2 with respect to medium 1.
Or Sine i/ Sine r = constant
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