Question

The refractive index of a rarer medium with respect to a denser medium is?

Answer 1

since the ray travels from a denser medium(glass) to a rarer medium(air), the ray of light will bend away from the normal, and hence the angle of refraction will be greater than angle of incidence. Hence the refractive index of air with respect to glass will be lesser than 1.

Answer 2

will be lesser than 1