The given plot shows the variation of U, the potential energy of interaction between two particles with the distance separating them r,

Options

A. (a) 1 and 3
B. (b) 1 and 4
C. (c) 2 and 4
D. (d) 2 and 3

Answer

C

Explanation

At point C the potential energy is minimum, hence it is a point of stable equilibrium. Also, from C to A, the slope is negative, i.e.,
`(dU)/(dr)lt0`
Hence, the force of interaction between the particles is repulsive between points C and A.