An object `O` is stuck on the surface of a transparent solid spher of radius 20 cm. Find refractive index of the sphere such that rays from the object after refraction from the opposite side emerge as a parallel beam, as shown Also prove that refractive index has the same value in the given situation for any value of radius of sphere.

Options

A. 1.5
B. 1.67
C. 2
D. 2.5

Answer

C

Explanation

`(mu_2)/(v)-(mu_1)/(u)=(mu_2-mu_1)/(R)`
`(1)/(infty)-(mu)/(-2R)=(1-mu)/(R)`
`(mu)/(2)=-1+mu`
`(mu)/(2)=1impliesmu=2.0`