The figure ,shows a transparent sphere of radius`R`and refractive index`mu`.An object `O`is placed at a distance `x` from the pole of the first surface so that a real image is formed at the pole of the exactly opposite surface.
if an object is Placed at a distance`R` from the pole of first surface ,then the real image is formed at a distance `R`from thepole of the second surface.The refractive index`mu` of the spher is given by
A. 1.5
B. `sqrt(2)`
C. 3
D. `4/3`