The ratio between the values of accelaration due to gravity at a height 1km above and at a depth of 1km below the earth's surface is (radius of earth is R)
As we learnt
Variation in 'g' with depth -
depth from the surface of earth
Value of g at depth 'd'
- wherein
'g' decreases on going below the surface of earth .
If h<<<<R then gravity at height
And gravity at depth d
At h=d=1km