A capillary tube is immersed vertically in water and the height of the water column is x. When this arrangement is taken into a mine of depth d, the height of the water column is y. If R is the radius of the earth, the ratio x/y is:

When the capillary is placed in water on the surface of earth, the acceleration due to gravity is g. Since, the rise in the capillary tube is directly proportional to the acceleration due to gravity, Hence, when the entire apparatus is taken into a mine of depth d, the value of acceleration due to gravity will become, g'(1-d/R). Thus, the rise in the capillary tube will be x, y in the 2 cases. So, x/y = g/g'(1-d/R) = 1/(1-d/R)