The relative permittivity and relative permeability of a medium are 3 and `(4)/(3)` respectively, the critical angle for this medium is

Options

A. `15^(@)`
B. `30^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

B

Explanation

If speed of light in medium is v, then `v=(1)/(sqrt(mu in))` and refractive index
`n = (c )/(v)`
`(1)/(sqrt((mu_(r )in_(r )))=n`
`sqrt((4)/(3)xx3)=n`
2 = n
`2=(1)/(sin C)`
`therefore sin C = (1)/(2)`
`therefore C = 30^(@)`