Medium MCQ +4 / -1 PYQ · JEE Mains 2022

The escape velocity of a body on a planet 'A' is 12 kms$-$1. The escape velocity of the body on another planet 'B', whose density is four times and radius is half of the planet 'A', is :

  1. A 12 kms<sup>$-$1</sup> Correct answer
  2. B 24 kms<sup>$-$1</sup>
  3. C 36 kms<sup>$-$1</sup>
  4. D 6 kms<sup>$-$1</sup>

Solution

<p>$${v_{esc}} - \sqrt {{{2GM} \over R}} = \sqrt {{{2G} \over R} \times \rho \times {4 \over 3}\pi {R^3}} $$</p> <p>$\Rightarrow {v_{esc}} \propto R\sqrt \rho$</p> <p>$\Rightarrow {{{{({v_{esc}})}_B}} \over {{{({v_{esc}})}_A}}} = 1$</p> <p>$\Rightarrow {({v_{esc}})_B} = 12$ km/s</p>

About this question

Subject: Physics · Chapter: Gravitation · Topic: Escape Velocity

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