JEE Main20231 Feb 2023Evening ShiftPhysicsGravitationActual
The escape velocities of two planets A a n d B are in the ratio 1 : 2 . If the ratio of their radii respectively is 1 : 3 , then the ratio of acceleration due to gravity of planet A to the acceleration of gravity of planet B will be:
Options
- A4 3
- B3 2
- C2 3
- D3 4
Correct answer
D. 3 4
Step-by-step solution
The formula to calculate the mass M of any planet of radius R and density ρ , considering it to be a sphere, is given by M =   4 3 π R 3 ρ . . . . . . . . . . . . . . . . . . . . . ( 1 ) The escape velocity v A for planet A can be expressed as V A = 2 G M A R A = 2 G ρ A 4 3 π R A 3 R A = C ρ A . R A . . . . . . . . . . . . . . . . . . . . . . . . . . . . ( 2 ) where, G is Gravitational constant and C =   8 π G 3 is a constant. Similarly, the escape velocity v B of plane