The figure represents two concentric shells of radii `R_(1)` and `R_(2)` and masses `M_(1)` and `M_(2)` respectively. The gravitational field intensity at the point `A` at distance `a (R_(1) lt a lt R_(2))` is

Options

A. `F_(P) =0`
B. `F_(Q)=(GM_(1)m)/(b^(2))`
C. `F_(R)=(G(M_(1)+M_(2)))/(c^(2))`
D. All are correct

Answer

D

Explanation

At P, F = 0
At Q, `F=(GM_(1)m)/(b^(2))`
At R, `F=(G(M_(1)+M_(2))m)/(c^(2))`.