Question

Derivation of expression relating numerical aperture with refractive indices of medium from which light is incident, core and cladding

Answer 1

Answer:

The refractive index of the core is ƞ1 and that of cladding is ƞ2. The figure below shows an optical fiber inside which light ray is focused. So, the ray XA is launched from denser medium to rarer medium by making an angle α with the fiber axis.

Explanation: