A point mass m is placed inside a spherical shell of radius R and mass M at a distance `R/2` form the centre of the shell. The gravitational force exerted by the shell on the point mass is

Options

A. `(GMm)/(R^2)`
B. `-(GMm)/(R^2)`
C. Zero
D. `4(GMm)/(R^2)`

Answer

C

Explanation

Gravitational field due to a spherical shell at as point inside the shell i.e. `rltR`
`E=0rArrg=0`
F=mE=0rArrF=mg=0`