Also we examine some tranparencies of charge distributions where 8 lines emanate per unit of charge. Paper masks are used to focus our attention near to and far away from the charge distributions. If close together, the field is strong there, weaker where further apart. Every line connects a positive charge with a negative charge. A positive charge serves as a source of lines, a negative charges as a sink.
Field lines behave as if there is a tendency for lines to repel one another.
Close enough to a point charge, the field lines resemble those of an isolated charge. Far enough away from a group of point charges, there is insignificant difference from a single charge of same magnitude as net charge. An important field for our consideration is the uniform electric field , a field that has the same magnitude and direction at all points. We will see in a few weeks that an infinite sheet of charge will be used to create the uniform E . This may be realized to a good approximation in the lab by hooking a battery to two isolated parallel metal plates so that they become oppositely charged.