A uniform,horizontal beam of light is incident upon a quarter cylinder of radius`R=5`cm and has a refractive index `2//sqrt(3)`.A patch on the table for a distance `'x'`from the cylinder is unilluminated ,find the value of `'x'`?

Answer

5 m

Explanation

Sin C = `(1)/(mu)` = (1)/(2//sqrt(3))`
`implies C = Sin^(-1) (sqrt(3))/(2) = 60^(@)`

`"cos"60^(@) = (R)/(R+x) implies x = R , x = 5 cm`