Question

Relative refractive index can be:

• A. equal to 1
• B. greater than 1
• C. smaller than 1
• D. None of these

Answer 1

Answer: (A), (B), (C)

The correct options are
A

equal to 1

B

greater than 1

C

smaller than 1

Relative refractive index of medium A w.r.t to medium B is the ratio of their absolute refractive index(R.I.)

Let R.I of medium A and medium B be ${\mu }_A$ and ${\mu }_B$ respectively.

${}_B{\mu }_A=\frac{{\mu }_A}{{\mu }_B}=\frac{V_{air}}{V_A}\times \frac{V_B}{V_{air}}=\frac{V_B}{V_A}{\therefore }_B{\mu }_A=\frac{V_B}{V_A}$
If $V_B=V_A{\Rightarrow }_B{\mu }_A=1$
If $V_B>V_A{\Rightarrow }_B{\mu }_A>1$
If $V_B<V_A{\Rightarrow }_B{\mu }_A<1$
Hence, the correct options are A, B and C.