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 if the object distance is less than 90 cm

Answer

C

Explanation

`(3//2)/(v) - (4//3)/(u) = (3//2 - 4//3)/(-10)`
`(3)/(2v) = (1)/(-60)- (4)/(3u)`
So `v= (2)/(3)`x-(ve)