A Level Physics Home Tutors in DHA Islamabad for Cambridge Students

An electric field line shows the direction of the force on a positive test charge at each point. At any single point the field has one direction — so two lines cannot cross there.

If they crossed, a test charge at the intersection would be told to accelerate in two directions at once, which is inconsistent with a well-defined field vector.

Useful reading rules

• Lines start on positive charge and end on negative (or at infinity in simple sketches)
• Closer lines mean stronger field
• Tangent to the line = field direction

A Level Physics students in DHA Islamabad can practise sketching fields for single charges, dipoles, and parallel plates without violating the no-cross rule.