Question

A point object is placed at centre of glass sphere of radius 6 cm, and refractive index = 1.5, The distance of virtual image from the surface

Answer 1

Heya

The object is kept at the centre of the sphere all the rays coming from it are normal to the surface of the sphere.
Therefore they will emerge out undecided.
The image will appear at the same place
i.e 6 cm from the surface.

Answer 2

A point sized object placed at center of a glass sphere.
This means that the incident ray coming is on normal i.e the incident ray is zero.

The image of the object will be formed there only.So the distance of the image from the surface of glass sphere is 6 cm.

Hope This Helps You!