Question

From Brewster's law, except for polished metallic surface, the polarising angle

• A. depends on wavelength and is different for different colours
• B. independent of wavelength and is different for different colours
• C. independent of wavelength and is same for different colours
• D. depends on wavelength and is same for different colours

Answer 1

Answer: (A)

depends on wavelength and is different for different colours

According to Brewster's law:
$\mu =tani$

where $\mu =$ refractive index of medium

$i=$ polarization angle

$i=ta{n}^{-1}\left(\mu \right)$ ..........(1)

$\mu =\frac{\text{speed of light in vacuum}}{\text{speed of light in medium}}=\frac{{\lambda }^m}{{\lambda }^o}$..........(2)
So,
from equation (1) and (2), we can conclude that:

$i=ta{n}^{-1}\left(\mu \right)=ta{n}^{-1}\frac{{\lambda }^m}{{\lambda }^o}$

Hence, we can say from the above expression that the the polarising angle depend on the wavelenth and used to be different for different color.
So, the correct option is $\left(A\right)$