Question

A dipole p is at a distance r from a point charge q and oriented so that p makes an angle with the vector r from q to p. Compute the force experienced by the dipole p and the charge q.

Answer 1

Explanation:

Earlier we discussed, and calculated, the electric field of a dipole: two equal and opposite charges that are “close” to each other. (In this context, “close” means that the distance d between the two charges is much, much less than the distance of the field point P, the location where you are calculating the field.) Let’s now consider what happens to a dipole when it is placed in an external field \stackrel{\to }{\text{E}}. We assume that the dipole is a permanent dipole; it exists without the field, and does not break apart in the external field.