Question

If gravitational field due to uniform thin hemispherical shell at point $P$ is $I,$ then the magnitude of gravitational field at $Q$ is (Mass of hemispherical shell is $M,$ radius is $R$ )

• A. $\frac{G M}{2 R^{2}}-I$
• B. $\frac{G M}{2 R^{2}}+I$
• C. $\frac{G M}{4 R}-I$
• D. $2I$ $-\frac{G M}{2 R^{2}}$

Answer 1

Answer: (A)

gravitational field due to $II$ at $P$ = gravitational field at $I$ at $Q$
At $P$ ,
$E_{I}+E_{II}=\frac{G \left(2 m\right)}{\left(2 R\right)^{2}}=\frac{G M}{2 R^{2}}$
$E_{I}=\frac{G M}{2 R^{2}}-E_{II}=\frac{G M}{2 R^{2}}-I$