If the critical angle for total internal reflection from a medium to vacuum is `30^(@)`, the velocity of light in the medium is

Options

A. `6 xx 10^(8) m//sec`
B. `3 xx 10^(8) m//sec`
C. `2 xx 10^(8) m//sec`
D. `1.5 xx 10^(8) m//sec`

Answer

D

Explanation

`._(m)mu_(a) = sin c = (v_(m))/(v_(a))`
`:. v_(m) = 3 xx 10^(8) xx sin 30 = 1.5 xx 10^(8)m//s`.