JEE PYQ: Gravitation Question 3
Question 3 - 2021 (17 Mar Shift 1)
The radius in kilometer to which the present radius of earth ($R = 6400$ km) to be compressed so that the escape velocity is increased 10 times is:
Show Answer
Answer: 64
Solution
$v_e = \sqrt{\frac{2GM}{R}}$. For $10v_e$: $10 = \sqrt{\frac{R}{R’}}$, so $R’ = \frac{R}{100} = \frac{6400}{100} = 64$ km.