The refractive index of a material will be less than unity when

Can absolute refractive index of any material be less than one? Why?

Can the absolute value of refractive index of a medium be less than unity ?

Can the absolute value of refractive index of a meduim be less than unity ?

Can the absolute value of refractive index of a medium be less than unity ?

Statement I : Relative refractive index of a medium can be less than unity. Statement II : The angle of incidence is equal to the angle of refraction.

Can relative refractive index of a medium w.r.t another be less than unity?

Define the term refractive index of a medium. Can it be less than 1 ?

Can the value of absolute refractive index of a medium be less than 1?