Q.

The escape velocity from a spherical planet A is 10 km/s. The escape velocity from another planet B whose density and radius are 10% of those of planet A, is ____ m/s.     [2026]
 

1 2005  
2 1000  
3 10010  
4 10002  

Ans.

(3)

Ve=2GMR=2G×ρ×4πR33RVeρ×R

(Ve)B(Ve)A=ρBρA×RBRA=0.1ρAρA×(0.1RARA)

(Ve)B(Ve)A=110×110

(Ve)B=10×10001010=10010 m/sec