(a) What do you mean by refractive index of one transparent medium with respect to another ? How is it related to absolute refractive indices of two media ? (b) Can absolute refractive index of a medium be less than one ? Given reason.

(a) What do you mean by refractive index of one transparent medium wit

1.	(a) What do you mean by refractive index of one transparent medium with respect to another ? How is it related to absolute refractive indices of two media ? (b) Can absolute refractive index of a medium be less than one ? Given reason.
Answer» Solution :(a) When a light RAY is refracted from medium number 1 into medium number 2, the relative refractive index of MEIDUM 2 w.r.t. medium `1(n_(21))` is given by : `n_(21) = ("Speed of light in medium 1" (v_(1)))/("Speed of light in medium 2"(v_(2)))` It is found that `n_(21) = (v_(1))/(v_(2)) = (n_(2) "(absolute refractive index of medium 2)")/(n_(1) "(absolute refractive index of medium 1)")` (B) No, absolute refractive index of a medium cannot have a value less than one. It is because speed of light in any given medium cannot be greater than the speed of light in vaccum.