Q.No.56: - When light travels from any material medium then why refractive index increases from unity and why refractive index is unity when light passes through vacuum?

Q.No.56: - When light travels from any material medium then why refractive index increases from unity and why refractive index is unity when light passes through vacuum?

Ans: - The light travels more slowly in materials so “v” decreases while “c” remains constant. So the ratio n=c/v increases as denominator decreases. On the other hand when light travels in vacuum then v=c and refractive index becomes n=c/v=v/v=1

The refractive index “n” is unity when light travels through vacuum.