Question

4. State the laws of refraction of light. If the speed of light in vacuum is 3X108 ms-1,
find the speed of light in a medium of absolute refractive index 1.5
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Answer 1

Answer:

(a) The two laws of refraction of light are as follows:

(i) The incident ray, the refracted ray and the normal at the point of coincidence, lie in the same plane.

(II) The second law of refraction is also known as Snell's law of refraction and it states that: the ratio of Sine of the angle of incidence to the sine of refraction is constant for a given pair of media. It establishes a relation between angle of incidence and angle of refraction.

It can be expressed mathematically as follows:



Given: The speed of light in vacuum is 3 x 108 ms

n=1.5

As we know that refractive index is given by the ratio of speed of light in vaccum to the speed of light in the medium