A spherical surface of radius of curvature R separates air (refractive index 1.0) from glass (refractive index 1.5). The centre of curvature is in the glass. A point object P placed in air is found to have a real image Q in the glass. The line PQ cuts the surface at a point O, and `PO=OQ`. The distance `PO`

Options

A. 5R
B. 3R
C. 2R
D. 1.5 R

Answer

A

Explanation

`(mu_2)/(v)-(mu_1)/(u)=(mu_2-mu_1)/(R)`
`((3)/(2))/(x)-(1)/(-x)=((3)/(2)-1)/(R)`
`((5)/(2))/(x)=((1)/(2))/(R)`
`x=5R`