JEE Main202313 Apr 2023Morning ShiftPhysicsGravitationActual
A planet having mass 9 M e and radius 4 R e , where M e and R e are mass and radius of earth respectively, has escape velocity in km s - 1 given by: (Given escape velocity on earth V e = 11 . 2 × 10 3 m s - 1 )
Options
- A67 . 2
- B16 . 8
- C11 . 2
- D33 . 6
Correct answer
B. 16 . 8
Step-by-step solution
The escape velocity on earth is given by V e  = 2 G M e R e Escape velocity for the planet is V ' e s c = 2 G ( 9 M e ) 4 R e       . . . ( i ) The escape velocity of earth is V e = 11 . 2 × 10 3   m   s - 1 From equation (i) V ' e s c = 9 4 2 G M e R e = 3 2 × 11 . 2 × 10 3   m   s - 1 ⇒ V ' esc = 16 . 8   km   s - 1