Question

Values for Brewster's angle can be

• A. only less than $45^{\circ }$
• B. only greater than $45^{\circ }$
• C. any value in the range $0^{\circ }$ to $90^{\circ }$ except $45^{\circ }$
• D. any value in the range $0^{\circ }$ to $90^{\circ }$ including $45^{\circ }$

Answer 1

Answer: (C)

Brewster's angle corresponding to two media of refractive indices $r_1$ and $r_2$ is
$\tan i_B=\left(\frac{n_2}{n_1}\right)$
Where, $n_2$ is refractive index of denser medium and $n_1$ is refractive index of rarer medium. If two mediums are same,
i.e. $n_1=n_2\Rightarrow \tan i_B=1$ or $i_B=45^{\circ }$
Polarisation is not possible if two mediums are same.
Therefore $i_B\ne 45^{\circ }$
Hence, Brewster's angle can have any value in the range $0^{\circ }$ to $90^{\circ }$ except $45^{\circ }$.