NTA Abhyas JEE Main2020PhysicsRay OpticsPractice
A ray of light is incident on a surface of glass slab at an angle 45 ° . If the lateral shift produced per unit thickness is 1 3 m , then the angle of refraction produced at the incident surface is
Options
- Atan - 1 3 2
- Btan - 1 1 - 2 3
- Csin - 1 1 - 2 3
- Dtan - 1 2 3 - 1
Correct answer
B. tan - 1 1 - 2 3
Step-by-step solution
Here, angle of incidence i = 45 ° L a t e r a l s h i f t d T h i c k n e s s o f g l a s s s l a b t = 1 3 Lateral shift d = t sin δ cos r = t sin ( i - r ) cos r ⇒ d t = s i n ( i - r ) cos r or d t = sin i cos r - cos i sin r cos r or d t = sin 45 ° cos r - cos 45 ° sin r cos r = cos r - sin r 2 cos r or d t = 1 2 1 - tan r or 1 3 = 1 2 1 - tan r or tan r = 1 - 2 3 or r = tan - 1 1 - 2 3