An optical fibre consists of core of  `mu_(1)`  surrounded by a cladding of  `mu_(2) lt  mu_(1)`
Channel: Doubtnut
Date: 2020-08-23

An optical fibre consists of core of  `mu_(1)`  surrounded by a cladding of  `mu_(2) lt  mu_(1)` . A beam of light enters from air at an angle `alpha`  with axis of fibre. The highest `alpha`  for which ray can be travelled through fibre is