18.5.4—The concept of electric potential leads to the electric potential energy of

A charge q at electric potential V has electric potential energy E_P=qV relative to the chosen zero; changes satisfy ∆E_P=q∆V.

Include the charge sign and reference level. A positive charge moving to lower V loses potential energy; a negative charge reverses that trend.

Moving a +2 μC charge through a 50 V rise increases potential energy by 1.0×10⁻⁴ J.

Potential is a property of the field location, whereas potential energy depends on both location and charge.