# What is the formula for the value of acceleration due to gravity at depth d from the surface of the earth ??

The value of acceleration due to gravity at depth d from the surface of the earth ( or at a general distance r=(R-d) from earth centre) is given by

$g'=g\left [ 1-\frac{d}{R} \right ]$

Where

g=Value of acceleration due to gravity  at the surface of the earth