Question

If the refractive index of ruby for light going from air to ruby will be $1.71$. What will be the refractive index for light going from ruby to air?

• A. $1.71$
• B. $0.58$
• C. $0.66$
• D. $1$

Answer 1

The correct option is B $0.58$

We know,

${}_a{\mu }_r=\frac{1}{{}_r{\mu }_a}$

Given, refractive index of ruby w.r.t. air

${}_a{\mu }_r=1.71$

$\therefore$ Refractive index for light going from ruby to air is given as

${}_r{\mu }_a=\frac{1}{{}_a{\mu }_r}=\frac{1}{1.71}=0.58$

Hence, the correct answer is OPTION B.