# Griffiths page 150

[SOLVED] Griffiths page 150

## Homework Statement

On this page, Griffith's start talking about "pure" and "physical" dipoles. Can someone define what these terms mean?

## The Attempt at a Solution

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siddharth
Homework Helper
Gold Member
Isn't it explained pretty clearly in the same page?

A physical dipole (one with a finite separation between charges)
Where exactly are you having difficulty?

Last edited:
D H
Staff Emeritus
A physical dipole comprises a pair of equal but opposite charges $q$ separated by a vector $2a\hat r$. The dipole moment is $2aq\hat r$. By decreasing the separation distance but increasing the charge you can keep the dipole moment constant. A pure dipole has a zero separation distance but a non-zero dipole moment. Such a thing is not physically realizable.

pam