KVPY2017PhysicsRay Optics
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
Options
- A2 t n²- ²
- B2 t n²- ²
- C2 t n ²- ²
- D2 t 1- ² n ²
Correct answer
A. 2 t n²- ²
Step-by-step solution
Therefore x = h ₁- h ₂ array l = d h ₁ & = d - L h ₂ x = d - d - L x = L array Snell's Law array l 1 = n r 1 r = n r = L 2 . t L =2 t r array L = 2 t n ²- ² array l x = 2 t n ²- ² = 2 t n ²- ² array