Gravitation Question 141
Question: The escape velocity from the earth is about 11 km/second. The escape velocity from a planet having twice the radius and the same mean density as the earth, is [NCERT 1980; MP PMT 1987; MP PET 2001, 2003; AIIMS 2001; UPSEAT 1999]
Options:
A) 22 km/sec
B) 11 km/sec
C) 5.5 km/sec
D) 15.5 km/sec
Show Answer
Answer:
Correct Answer: A
Solution:
$ [v_{e}=\sqrt{\frac{2GM}{R}}=R\sqrt{\frac{8}{3}\pi G\rho }] $ $ [v_{e}\propto R] $ if r = constant Since the planet having double radius in comparison to earth therefore the escape velocity becomes twice i.e. 22 km/s.
