Read Zero-Potential Loci for Unequal Point Charges
Potential is scalar, so a zero-potential locus comes from an algebraic relation between distances—not from balancing field vectors.
Electricity questions depend on identifying charge, a conducting path and the condition that controls current or magnetic effect.
Separate charge, current and the path between them
Charge is a property · current needs a conducting path
Charge is a property; current needs a conducting path. Decide first whether the question concerns charging, resistance, current or earthing.
Set the scalar sum to zero
This becomes a fixed distance ratio r₁/r₂.
Recognise the geometry
The locus of points with a fixed ratio of distances from two fixed points is generally an Apollonius circle. Equal and opposite charges are the special case that gives a perpendicular bisector.
Do not mix field and potential
At zero potential, the electric field is not necessarily zero; its vector contributions usually do not cancel there.
OlympIQ exam lens
- ✓Add potentials as scalars.
- ✓Turn the equation into a distance ratio.
- ✓Identify the locus before checking options.
The midpoint is zero-potential only for equal and opposite charges—not for unequal charges.
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