# There are two concentric shells of masses m1 and m2 and radii R1 and R2 (R2 > R1). The force on a particle of mass m0 kept at a distance r form the common centre is F. Then,

Q:There are two concentric shells of masses m1 and m2 and radii R1 and R2 (R2 > R1). The force on a particle of mass m0 kept at a distance r form the common centre is F. Then,

(a) $F = \frac{G(m_1 + m_2)m_0}{r^2}$ ; when r > R2

(b) $F = \frac{G m_1 m_0}{r^2}$ ; when R1 < r > R2

(c) F = 0 ; when r < R1

(d) $F = \frac{G m_1 m_2}{r^2}$

Ans: (a) , (b), (c)