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)))`
