Which one of the following plots represents the variation of gravitational field on a particle with distance r due to a thin spherical shell of radius R? (r is measured from the centre of the spherical shell)

Options

A.
B.
C.
D.

Answer

B

Explanation

Gravitational field due to the thin spherical shell.
Inside the shell, F = 0 (for `rltR`)
On the surface of the shell,
`F=(GM)/(r^2)` (for r = R)
Outside the shell,
`F=(GM)/(r^2)` (for `rgtR`)
The variation of F with distance r from the centre is as shown in the figure (b).