• # question_answer                                                                   The gravitation field (g) inside the earth is proportional to r as (where, r is distance from the centre) A)  $\frac{1}{r}$                                   B)  $\frac{1}{{{r}^{2}}}$ C)  ${{r}^{2}}$                                       D)  $r$

Idea Here, earth is considered as a solid sphere of mass in mass Mg. The intensity of gravitational field is equal to$\frac{G{{M}_{e}}}{R_{r}^{3}}r$ ${{g}_{\text{inside}}}=\frac{G{{M}_{e}}r}{R_{e}^{3}}\Rightarrow {{g}_{\text{inside}}}\propto r$ TEST Edge Shell of uniform mass distribution of mass M (i) Force on ${{m}_{1}}$ due to shell = zero. (ii) Force on ${{m}_{2}}$ due to shell $=\frac{GM{{m}_{2}}}{r_{2}^{2}}$