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

Options

A. `3xx10^(8)ms^(-1)`
B. `1.5xx10^(8)ms^(-1)`
C. `sqrt3xx10^(8)ms^(-1)`
D. `2xx10^(8)ms^(-1)`

Answer

B

Explanation

`n=(1)/(sini_(c))=(1)/(sin 30^(@))=2`
`therefore" Speed of light in the medium v"=(c)/(n)=(3xx10^(8))/(2)=1.5xx10^(8)ms^(-1)`