Question

The critical angle for a ray travelling from an unknown medium to vacuum is 30°. Then refractive index of that unknown medium is
(A) 1.5
(B) 2
(C) 2.5
(D) 1​

Answer 1

Answer:

Let refractive index denoted by n and critical angle by c

we know, n= 1/sin c

n= 1/ sin 30°

n= 1/ 0.5

n= 2

option b  

Answer 2

Answer:

2 is your answer mate ok