Pulfrich refractometer is used to measure the refractive index of solids and liquid. It consist of right angled prism. A having its two faces perfectly plane. One of the face is horizontal and the other is vertical as shown is figure. The solid B whose refractive index is to be determined is taken having two faces cut perpendicular to one another. Light is incident in a direction parallel to the horizontal surface so that the light entering the prism A is at critical angle C. Finally, it emerges from the prism at an angle i. Let the refractive index of the solid be `mu` and that of the prism A be `mu_(0)` (which is known). Here `mu_(0)gtmu` and by measuring i, `mu` can be determinged.

Q. Refractive index of the solid `(mu)` in terms of `mu_(0)` and i is

Options

A. `sqrt(2)`
B. `sqrt(3)`
C. slightly greater than 2
D. slightly less than 2

Answer

c.

Explanation

Here `30^(@)gtC`
`rArrsin30^(@)gtsinC`
`rArr (1)/(2)gt (1)/(mu_(0))rArr mu_(0)gt2`