Easy MCQ +4 / -1 PYQ · JEE Mains 2023

The ratio of escape velocity of a planet to the escape velocity of earth will be:-

Given: Mass of the planet is 16 times mass of earth and radius of the planet is 4 times the radius of earth.

  1. A $1: 4$
  2. B $1: \sqrt{2}$
  3. C $4: 1$
  4. D $2: 1$ Correct answer

Solution

The escape velocity of a planet or a celestial body is given by:<br/><br/> $v_e = \sqrt{\frac{2GM}{r}}$<br/><br/> where $G$ is the gravitational constant, $M$ is the mass of the planet, and $r$ is the radius of the planet. <br/><br/> Let the subscripts "p" and "e" denote the planet and earth, respectively. Then, we have:<br/><br/> $$\frac{v_{e,p}}{v_{e,e}} = \frac{\sqrt{\frac{2G M_p}{r_p}}}{\sqrt{\frac{2G M_e}{r_e}}} = \sqrt{\frac{M_p r_e}{M_e r_p}}$$ <br/><br/> Substituting the given values, we get:<br/><br/> $\frac{v_{e,p}}{v_{e,e}} = \sqrt{\frac{16 \cdot 1}{1 \cdot 4}} = \sqrt{4} = 2$ <br/><br/> Therefore, the ratio of the escape velocity of the planet to that of earth is 2 : 1.

About this question

Subject: Physics · Chapter: Gravitation · Topic: Kepler's Laws

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