Uniform electric fields — common mistakes

Be careful with units! Electric field strength can be expressed as V m⁻¹ (Volts per metre) or N C⁻¹ (Newtons per Coulomb). Understand that these are equivalent and choose the most convenient for your calculation. Always state direction for vector quantities like force or electric field strength.

Uniform fields have constant strength and direction, represented by parallel lines. Radial fields (from point charges) have strength that decreases with distance and lines that spread out from a central point.

When a particle enters perpendicular to the field, it experiences a constant electric force (and thus constant acceleration) in one direction, while maintaining constant velocity in the perpendicular direction. This combination of motions results in a parabolic trajectory, analogous to projectile motion under constant gravity.

This perpendicularity means that no component of the electric force acts along the equipotential line. Therefore, no work is done by the electric field when a charge moves along such a line, consistent with the definition of equal potential.