Two concentric spherical shells have masses `m_(1)`, `m_(2)` and radit `R_(1)`,`R_(2) (R_(1) lt R_(2))`. Calculate the force by this system on a particle of mass `m`, if it is placed at a distance `((R_(1) + R_(2)))/(2)` from the centre.

Answer

A, B, D

Explanation

Particle lies between two shells. Therefore, net force in exerted only by the inner shell.
`:. F = (Gm_(1)m)/(((R_(1) + R_(2))/(2))^(2)) = (4 Gm_(1) m)/((R_(1) + R_(2))^(2))`