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Back surface of a glass (refractive inde...

Back surface of a glass (refractive index n and thickness t) is polished to work as a mirror as shown below. A laser beam falls on it and is partially reflected and refracted at the air-glass interface and fully reflected at the mirror surface respectively. A pattern of discrete spots of light is observed on the screen.

The spacing between the spots on the screen will be

A

`(2tcostheta)/(sqrt(n^(2)-sin^(2)theta))`

B

`(2tsintheta)/(sqrt(n^(2)-sin^(2)theta))`

C

`(2t tantheta)/(sqrt(n^(2)-sin^(2)theta))`

D

`(2tsintheta)/(sqrt(1-(sin^(2)theta)/(n^(2)))`

Text Solution

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The correct Answer is:
A
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