An electric field is a region where a charge feels a force. The field strength is the force per unit positive charge, E = F / q, and field lines map its shape: they leave positive charges and enter negative ones, and the force on a positive charge points along them. Step through the patterns below.
MissionPredict the direction of the force on a positive test charge.Streak 0Best 0
Field lines point in the direction of the force on a positive charge. That direction is:
patternsingle positive
field strengthE = F / q
Red is a positive charge, blue is negative. The gold dot is a positive test charge; the arrow on it is the force F = qE, always along the field line.