Problem 3.285

A long thin cylindrical rod made of paramagnetic with magnetic susceptibility \(\chi\) and having a cross-sectional area \(S\) is located along the axis of a current-carrying coil. One end of the rod is located at the coil centre where the magnetic induction is equal to \(B\) whereas the other end is located in the region where the magnetic field is practically absent. What is the force that the coil exerts on the rod?