At which condition Snell\'s law is not applicable?

1.	At which condition Snell\'s law is not applicable?
Answer» At the point of total internal reflection.When the sin of the angle of reflection is greater than one.For the normal incidence of light on a refractive surface angle of refraction r =0But according to snell\'s lawsin i /sin r = n (refractive index)i.e, denominator becomes zero which is a indeterimant form like in diamond once the ray of light enters it,it doesn\'t come out this is known as total internal reflection and the angle is called as critical angle of reflection.

Discussion