Question

Explain optical path length and derive the law of reflection of light​

Answer 1

In optics , optical path length means the length of light has to travel in air to create the same phase difference. It is the product of the geometric length of the path light follows through the system and the index of refraction of the medium through which it propagates. 

The optical path length is simply the distance the light travels times the refractive index. For example , light travelling through 10cm of water has an optical path length of 10×1.333 or 13.3cm. The geometric length is simply the physical distance of the light travel. The optical path length is important because it allows us to find out what the phase of the light will be at any point , where as the geometrical length doesn't. 

Answer 2

Explanation:

In optics , optical path length means the length of light has to travel in air to create the same phase difference. It is the product of the geometric length of the path light follows through the system and the index of refraction of the medium through which it propagates.

The optical path length is simply the distance the light travels times the refractive index. For example , light travelling through 10cm of water has an optical path length of 10×1.333 or 13.3cm. The geometric length is simply the physical distance of the light travel. The optical path length is important because it allows us to find out what the phase of the light will be at any point , where as the geometrical length doesn't.

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