Field lines
Lines that show the direction of the field. They start on positive charge, end on negative charge, and are closer where the field is stronger.
Last updated
Analogy
Wind arrows on a weather chart.
Example
Dense lines: strong field.Parallel lines: uniform field.Start +, end -.
In practice
Field lines never cross because the field has one direction at each point.
Practice
Flashcards
- Where do field lines start and end?Start on positive charge and end on negative charge.
Questions people ask
Why can't field lines cross?
If two lines crossed, the field at the crossing point would have two directions at once. A charge placed there would not know which way to be pushed. The field has one definite direction at every point, so the lines of force can only touch at a zero-field point or end on charges.
What do equipotential lines show?
Equipotential lines connect points at the same voltage. They always cross field lines at right angles, and no work is done moving a charge along one. Like contour lines on a map, close lines mean a steep change and a strong field.