Question

define the expression for acceleration due granules at depth 'd' from the surface of earth​

Answer 1

The mass density of the shaded sphere is equal to mass density of the bigger sphere. i.e. M′43πr3=M43πR3 . ... We get, ⇒g=GM(R−d)R3. Therefore the expression of acceleration due to gravity of a body at a depth d from the surface of earth is GM(R−d)R3.