Physics - Wave Optics Question with Solution | TestHub

According to Brewster's law, the refractive index of glass with respect to air is given by:

$\mu =\tan \theta$

The refractive index is also the ratio of the wavelength of light in air to the wavelength of light in glass:

$\mu =\frac{{\lambda }_a}{{\lambda }_g}$

Equating the two expressions for $\mu$:

$\frac{{\lambda }_a}{{\lambda }_g}=\tan \theta$

${\lambda }_g=\frac{{\lambda }_a}{\tan \theta }$

${\lambda }_g={\lambda }_a\cot \theta$

Answer: ${\lambda }_g={\lambda }_a\cot \theta$