Spark image

Electric fields

An electric field exists around all electrical charges. The direction of the field is shown by a line of force and these lines show the direction of the force on a positive charge at a given point. The lines therefore go from positive to negative.

The two most important types of electric field as far as this level of study is concerned are radial fields (Figure 1) and uniform fields (Figure 2). A radial field is that which exists round a point charge while a uniform field would exist between two plates as shown in the diagram. We have to simplify things a little - no charge is truly a point and there will always be some variations in the field at the edges of parallel plates.

Notice that the radial field looks just like that round a planet when viewed from a distance and the uniform field is like that close to the Earth's surface.

Some other simple electrical fields are shown in Figures 3, 4 and 5.

© Keith Gibbs 2011