KCET2010PhysicsRay Optics
A, B and C are the parallel sided transparent media of refractive indices n ₁, n ₂ and n ₃ respectively. They are arranged as shown in the figure. A ray is incident at an angle i on the surface of separation of A and B which is as shown in the figure. After the refraction into the medium B , the ray grazes the surface of separation of the madia B and C. Then, i equals to
Options
- An ₃ n ₁
- Bn ₁ n ₃
- Cn ₂ n ₃
- Dn ₁ n ₂
Correct answer
A. n ₃ n ₁
Step-by-step solution
Applying Snell's law between the surfaces A and B n ₁ i = n ₂ r ₁ ...(i) Again applying Snell's law between surfaces B and C n ₂ r ₁= n ₃ r ₂ ...(ii) From Eqs. (i) and (ii), we get aligned Here, & n ₁ i &= n ₃ r ₂ & r ₂ &=90^ & n ₁ i &= n ₃ & & i &= n ₃ n ₁ aligned