Question

A ray of light in air is incident at an angle of `45^(@)` on the surface of separation of a medium. It is refracted in the medium at an angle of `30^(@)`. What is the velocity of light in that medium ?
A. `1.5xx10^(8) m//s `
B. `2.12xx10^(8) m//s `
C. `3.5xx10^(8) m//s `
D. `3.33xx10^(8) m//s `

Answer 1

Correct Answer - B
`n=(sin 45^(@))/(sin 30^(@))=((1)/(sqrt(2)))/(1/2)=sqrt(2)=1.414`
`n=(V_a)/(V_m) :. V_m=(V_a)/(n)=(3 xx 10^(8))/(1.414) = 2.12 xx 10^(8) m//s `