Question

A light of wavelength $6000A^0$ in air, enters a medium with refractive index 1.5. What will be the wavelength of light in the medium?

• A. $4000A^0$
• B. $6000A^0$
• C. $9000A^0$
• D. None of the above

Answer 1

The correct option is A $4000A^0$

Here, wavelength of light in air,
$\lambda =6000A^0=6\times {10}^{-7}m;$
Refractive index of the medium, $\mu =1.5$
The frequency of the light does not change, when light travels from air to a refracting medium.
$\therefore v^{\prime }=v=\frac{c}{\lambda }=\frac{3\times {10}^8}{6\times {10}^{-7}}=5\times {10}^{14}{S}^{-1}$
The wavelength of light in the medium,
${\lambda }^{\prime }=\frac{\lambda }{\mu }=\frac{6000}{1.5}=4000A^0$