I keep getting “Equipotential surfaces” questions wrong in Electrostatic Potential & Capacitance. What's the trap?
thinking zero work along the surface means the electric field is zero there.
The usual trap: thinking zero work along the surface means the electric field is zero there. How to avoid it: the field may be strong, but it has no component along an equipotential. Go back to the definition — Moving a charge along an equipotential surface requires no work by or against the electrostatic field. Electric-field lines cross equipotentials at right angles.
Key point
Equipotential surfaces
Common mistake
thinking zero work along the surface means the electric field is zero there.
Memory tip
the field may be strong, but it has no component along an equipotential.
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