Calculate the time which light will take to travel normally through a glass plate of thickness `1 mm`. Refractive index of glass is `1.5`.

Answer

`5 xx 10^(-12) s`

Explanation

`t = ?, x = 1 mm = 10^(-3)m`
vel. of light in glass,
`v = (c )/(mu) = (3 xx 10^(8))/(1.5) = 2 xx 10^(8) m//s`
`t = (x)/(v) = (10^(-3))/(2 xx 10^(8)) = 5 xx 10^(-12)s`