INSTRUMENT 03 / FIELD TABLE
Electric potential
and field.
Arrange electric charges and inspect the field they create. The color shows potential; arrows show the force direction a positive test charge would feel.
ELECTRIC POTENTIAL V(x,y)− NEGATIVE POSITIVE +
YELLOW CROSSHAIR = PROBE2 SOURCES · 340 VECTOR SAMPLES
Where does a positive test charge want to go?
REPRESENTATIVE EQUATIONV(r) = k Σ qᵢ / |r − rᵢ|
Vectors leave positive charge and enter negative charge. The midpoint has zero potential but not zero field. The colored surface is electric potential: it tells you how much energy a positive test charge would have at each point. The arrows show the related electric field, which points down the steepest slope of that potential, E = −∇V.
Nothing here is drawn from a memorized field-line picture. At every sample point, the model adds the Coulomb contribution from each charge. Moving one source changes the whole map because every source contributes everywhere.