A concave spherical surface of radius of curvature `10 cm` separates two mediums `X` and `Y` of refractive indices `4//3` and `3//2` respectively. Centre of curvature of the surfaces lies in the medium `X`. An object is placed in medium `X`.

Options

A. Image is always real
B. Image is real if the object distance is greater than `90`cm
C. Image is always virtual
D. Image is virtual only if the object distance is less then `90` cm

Answer

C

Explanation

(Moderate) Let there be two point objects `O_(1)` and `O_(2)`. Incident rays from `O_(1)` and `O_(2)` at point `P` shall both bend towards normal and hence the corresponding refracted rays shall intersect the principal axis in the left medium. Therefore image formed under given condition shall always be virtual.