Question

What should be the maximum acceptance angle at the air-core interface of an optical fibre if $n_1$ and $n_2$ are the refractive indices of the core and the cladding, respectively

• A. ${\sin }^{-1}\left(\frac{n_2}{n_1}\right)$
• B. ${\sin }^{-1}\sqrt{n_1^2-n_2^2}$
• C. $\left[{\tan }^{-1}\frac{n_2}{n_1}\right]$
• D. $\left[{\tan }^{-1}\frac{n_1}{n_2}\right]$

Answer 1

The correct option is B ${\sin }^{-1}\sqrt{n_1^2-n_2^2}$