When the angle of incidence is `60^(@)` on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is

Options

A. ` sqrt 2 xx 10^(8) ms ^(-1)`
B. `sqrt3 xx 10^(8) ms^(-1)`
C. `2 xx 10^(8) ms^(-1)`
D. `3 xx 10^(8) ms^(-1)`

Answer

B

Explanation

`.^(a)mu_(g) = tan theta_(P)` where `theta_(P)` = polarising angle.
or `.^(a)mu_(g) = tan 60^(@)`
or `(v)/(v_(g)) = sqrt 3`
or `v_(g) = (c)/(sqrt3)` = `(3 xx 10^(8))/(sqrt3)` = `sqrt3 xx 10^(8) ms^(-1)`