The earth is an approximate sphere. If the interior contained matter which is not of the same density everywhere, then on the surface of the earth, the acceleration due to gravity.

Options

A. will be directed towards the centre but not the same everywhere
B. will have the same value everywhere but not directed towards the centre
C. will be same everywhere in magnitude directed towards the same
D. cannot be zero at any point

Answer

D

Explanation

If we assume the earth as a sphere of uniform density, then it can bee treated as point mass placed at its centre. In it is is not so, if the earth is considered as a sphere of non-uniform density, in that case value of g will be different at different points and cannot be zero at any point.