A cylinderical optical fibre (quarter circular  shape) of refractive index `n = 2` and diameter `d
Channel: Doubtnut
Date: 05/04/2020

A cylinderical optical fibre (quarter circular  shape) of refractive index `n = 2` and diameter `d = 4mm` is surrounded by air. A light beam is sent into the fibre along its axis as shown in figure. Then the smallest outer radius `R` (as shown in figure) for which no light escapes after incident on curved surface of fibre is:  src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/RES_DPP_PHY_XII_E01_166_Q01.png" width="80%