Question

A ray of light in a transparent medium falls on a surface separating the medium from air atom angle of incidence 45ºthe ray undergoes TIR. If n is the refractive index of the medium with respect to air, select the possible values of n from the following. 

(a) 1.3 

(b) 1.4 

(c) 1.5 

(d) 1.6

Answer 1

Correct Option :-  (b) 1.4 

Explanation :-

For T.I.R. to take place sin i > sin θc 

Sin 45º > sin θc 

1/√2 > 1/n 

√2 = 1.414 

n > 1.414 

the possible values of n can be 1.5 or 1.6