Question

Light wave of frequency $4\times {10}^{14}$ Hz passes through a medium. The wave length in the medium is $\lambda =5\times {10}^{-7}$ m. The refractive index of the medium is:

• A. $\frac{2}{3}$
• B. $\frac{4}{3}$
• C. $\frac{3}{2}$
• D. $1.414$

Answer 1

The correct option is C $\frac{3}{2}$

Frequency $=\frac{speedinmedium}{wavelengthinmedium}$
$=\frac{speedinvacuum/\mu }{wavelengthinmedium}$
$4\times {10}^{14}=\frac{3\times {10}^8}{\mu \times 5\times {10}^{-7}}$
$\mu =\frac{3\times {10}^8}{4\times {10}^{14}\times 5\times {10}^{-7}}$
$=\frac{3}{2}$