Question

The Brewsters angle $i_b$ for an interface should be:

• A. $0< i b < 30$
• B. $30< i_b < 45$
• C. $45< i_b < 90$
• D. $i_b = 90$

Answer 1

Answer: (C)

$45< i_b < 90$

Answer 2

Brewster's angle is the angle at which light with a specific polarization passes through a dielectric surface without any reflection. When unpolarized light hits the surface at this angle, the reflected light is completely polarized.

Calculation:

At the interface, Brewster's angle $i_b$​ is given by: $μ=tan⁡i_b \ (1)$

Here, $\mu$ is the refractive index of the material, which ranges from 1 to ∞: $1 < \mu < \infty$

Substituting equation (1) into this range, we get: $1 < \tan i_b < \infty$

Therefore, the polarization angle $i_b$ falls within: $\tan^{-1}(1) < i_b < \tan^{-1}(\infty)$
$\Rightarrow 45^\circ < i_b < 90^\circ$