What should be the maximum acceptance angle at the aircore interface of an optical fibre if 1 n and 2 n are the refractive indices of the core and the cladding, respectively

Options

A. `sin^(-1)(n_(2)//n_(1))`
B. `sin^(-1) sqrt(n_(1)^(2)-n_(2)^(2))`
C. `[ tan^(-1)(n_(2))/(n_(1))]`
D. `[tan^(-1)(n_(1))/(n_(2))]`

Answer

B

Explanation

Core of acceptance angle `theta=sin^(-1)sqrt(n_(1)^(2)-n_(2)^(2))`.