Refraction of light — UPSC Physics Optional CSE 2023 Paper I

Write conditions for working of a step-index optical fiber. In a step-index fiber, the core and cladding materials have refractive indices 1\cdot50 and 1\cdot43, respectively. Find the following : (i) Critical propagation angle (ii) Acceptance angle (iii) Total time delay in 1\text{ km} length of the fiber (iv) Total dispersion in 50\text{ km} length of the fiber