(c) In an optical fibre, if n 1 and n 2 are the refractive indices of the core and cladding, then which among the following, would be a correct equation?
(i) n 1 < n 2
(ii) n 1 = n 2
(iii) n 1 << n 2
(iv) n 1 > n 2
Optical Fibres work on the principle of total internal reflection .
The main conditions for total internal reflection are:
- Light should travel from denser to rarer medium.
- Angle of incidence should be greater than critical angle
The refractive index of the core is greater than the refractive index of the cladding.
So the correct answer is (iv)