Q 11-07-196JEE MainJEE Main 2017 (2 Apr)Easy
The variation of acceleration due to gravity $g$ with distance $d$ from the centre of the earth is best represented by ($R$ = Earth's radius):
Answer: (A) see figure
Treat the earth as a uniform sphere.
- Inside ($d < R$): only the mass within radius $d$ attracts, $g = \dfrac{GM}{R^3}d$, which increases linearly from zero at the centre.
- Outside ($d \ge R$): $g = \dfrac{GM}{d^2}$, which falls off as $1/d^2$.
So $g$ rises along a straight line to its maximum at $d = R$ and then decreases along a curve. This is graph (1).
Solution by Sreeraj P, M.Sc Physics