JEE PYQ: Gravitation Question 36
Question 36 - 2019 (09 Apr Shift 1)
A solid sphere of mass $M$ and radius $a$ is surrounded by a uniform concentric spherical shell of thickness $2a$ and mass $2M$. The gravitational field at distance $3a$ from the centre will be:
(1) $\frac{2GM}{9a^2}$
(2) $\frac{GM}{9a^2}$
(3) $\frac{GM}{3a^2}$
(4) $\frac{2GM}{3a^2}$
Show Answer
Answer: (3)
Solution
At $r = 3a$: total mass enclosed $= M + 2M = 3M$. $E = \frac{G(3M)}{(3a)^2} = \frac{3GM}{9a^2} = \frac{GM}{3a^2}$.
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