Question

Optical fibres are generally composed of silica, which has a refractive index of 1.44. How

fast does light travel in silica fibre?

Answer 1

from formula,

n = speed of light

speed of light in medium

In Silica,

1.44 = (3e8m/s)/v

v= (3e8m/s)/1.44

v = 20.83e7m/s

v = 20.8 × 10^7m/s.

Light travels in silica at 20.8 × 10^7 m/s.