JEE Main20205 Sep 2020Morning ShiftPhysicsGravitationActual
The value of the acceleration due to gravity is g 1 at a height h = R 2 ( R = radius of the earth) from the surface of the earth. It is again equal to g 1 at a depth d below the surface the earth. The ratio d R equals:
Options
- A4 9
- B5 9
- C1 3
- D7 9
Correct answer
B. 5 9
Step-by-step solution
Given that g n = g d G M ( R + h ) 2 = G M R 3 ( R - d ) G M ( R + R / 2 ) 2 = G M R 3 ( R - d ) 4 G M 9 R 2 = G M R 2 1 - d R 4 9 = 1 - d R d R = 1 - 4 9 = 5 9 d = 5 9 R