Calculate force on a dipole in the surrounding of a long charged wire as shown in the figure.

Explanation

In the situation shown in figure, the electric field strength due to the wire, at the position of dipole as `E=(2klambda)/(r)`
Thus force on dipole is `F=-p. (dE)/(dr)=-p[-(2klambda)/r^(2)]=(2kplambda)/r^(2)`
Here -ve charge of dipole is close to wire hence net force an dipole due to wire will be attractive.