NTA Abhyas JEE Main2020PhysicsGravitationPractice
The radii of two planets are R 1 and R 2 and their densities are ρ 1 and ρ 2 respectively. If g 1 and g 2 represent the acceleration due to gravity at their respective surfaces, then g 1 g 2 is
Options
- Aρ 1 R 2 2 ρ 2 R 1 2
- Bρ 1 R 1 2 ρ 2 R 2 2
- Cρ 2 R 1 ρ 1 R 2
- Dρ 1 R 1 ρ 2 R 2
Correct answer
D. ρ 1 R 1 ρ 2 R 2
Step-by-step solution
The value of g at surface g = Gm e R e 2 = G R e 2 . 4π 3 R e 3 ρ g = 4 3 π G R ρ So, g 1 g 2 = 4 3 π G R 1 ρ 1 4 3 π G R 2 ρ 2 ⇒ g 1 g 2 = R 1 ρ 1 R 2 ρ 2