Question

(a) The refractive index of glass is `1.5`. What is the speed of light in glass ? (Speed of light in vaccum is `3 xx 10^(8) ms^(-1)`).
(b) Is the speed of light in glass independent of colour of light ? If not, which of the two colours, red and violet travels slower in a glass prism ?

Answer 1

Refractive index of a medium `n_(m)`=Speed o flight in vacuum/ Speed of light in the medium
Speed of light in vacuum, `c = 3 x× 10^(8) m s^(−1)`
Refractive index of glass, `n_(g)` = 1.50
Speed of light in the glass, v=Speedof light in vacuum/Refractive index of glass `=c//n_(g)`
`=3xx10^(8)//1.50=2xx10^(8)ms^(-1)`.