**Goal:** Hone the concept of electric field

**Source:** 283-340 Where is E zero near a dipole? 9/21

Where,

other than at infinity, is the electric field 0 in the vicinity of the

dipole shown?

- Along the y-axis.
- At the origin.
- At two points, one to the right of (a, 0), the other to the left of (-a,

0). - At two points on the y-axis, one below the origin, one above the origin.
- None of the above.

## Commentary:

## Answer

(5) Students have a lot of difficulty distinguishing electric field from

potential. Students already exposed to the concept of potential

frequently respond that the field is zero along the y-axis. If there are

many confused students, before identifying the correct response, it

helps to have the students draw the field lines.