Question

$\lambda_{a}$ and $\lambda_{m}$ are the wavelengths of a beam of light in air and medium respectively. If $\theta$ is the polarising angle, the correct relation between $\lambda_{a}, \lambda_{m}$ and $\theta$ is

• A. $\lambda_{\text {a }}=\lambda_{m} \tan ^{2} \theta$
• B. $\lambda_{m}=\lambda_{a} \tan ^{2} \theta$
• C. $\lambda_{a}=\lambda_{m} \cot \theta$
• D. $\lambda_{m}=\lambda_{a} \cot \theta$

Answer 1

Answer: (D)

We know, $\lambda_{m}=\frac{\lambda_{ a }}{\mu}$
and $\mu=\tan \theta$
$\therefore \lambda_{m}=\frac{\lambda_{ a }}{\tan \theta}=\lambda_{ a } \cot \theta$