JEE PYQ: Gravitation Question 14
Question 14 - 2021 (25 Feb Shift 1)
Given below are two statements: one is labelled as Assertion A and the other is labelled as reason R.
Assertion A: The escape velocities of planet A and B are same. But A and B are of unequal mass.
Reason R: The product of their mass and radius must be same. $M_1 R_1 = M_2 R_2$.
(1) Both A and R are correct but R is NOT the correct explanation of A
(2) A is correct but R is not correct
(3) Both A and R are correct and R is the correct explanation of A
(4) A is not correct but R is correct
Show Answer
Answer: (2)
Solution
$v_e = \sqrt{\frac{2GM}{R}}$. For same $v_e$: $\frac{M_1}{R_1} = \frac{M_2}{R_2}$, not $M_1 R_1 = M_2 R_2$. A is true (different masses can give same escape velocity) but R is false.
BETA
