The refractive index of glass is 1.5. The speed of light in glass is

Options

A. `3 xx 10^(8)` m//s
B. `2 xx 10^(8)` m/s
C. `1 xx 10^(8)` m/s
D. `4 xx 10^(8)` m/s

Answer

B

Explanation

From Snell's law of refraction,
`(sini)/(sinr) = mu_(2)/mu_(1) = v_(1)/v_(2)`
Given, `v_(1) = 3 xx 10^(8) m//s`
`mu_(2)/mu_(1) = ^(1)mu_(2) = 1.5`
`rAr v_(2) = 3 xx 10^(8)m//s`
`mu_(2)/mu_(1) = (v_(1)/mu_(2)^(1))= (3 xx 10^(8))/1.5 m//s`
`therefore v_(2) = (3 xx 10^(8))/(3//2) = 2 xx 10^(8) m//s`