Electric Field

Module 4.1: Two Positive Charges

Q1.	At what point(s) in space do you expect E to be exactly zero?
	Origin
	y-axis
	Right next to either of the charges
Q2.	What is the direction of E at an arbitrary point on the positive y-axis?
	- direction
	- - direction
	- direction
	- - direction
Q3.	What is the voltage V at the origin?
	Zero
	1/(12 0)
	1/(6 0)

Equipotential contour

An equipotential contour is a contour of points in space having the special feature that the potential (voltage) is the same at all those points. For point charges located in the x-y plane, the equipotential contour (in the x-y plane) for a specific voltage level, say V₁, can be identified by setting the expression for V(x,y) due to the charges equal to V₁ and then solving for a parametric equation between x and y. Thus, for N charges:

Of course, not every value of V₁ has a solution. For example, if all the charges are positive, V₁ cannot assume negative values.

Proceed to Module 4.2