Electric interaction energy for two point charges depends on their signed charge product and separation.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §19.1 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Electric interaction energy for two point charges depends on their signed charge product and separation. With zero energy at infinite separation, like-charge pairs have positive energy and unlike-charge pairs negative energy.
| Symbol | Meaning | Units |
|---|---|---|
| Energy (electric potential) | ||
| Coulomb's Constant | ||
| Electric charge (1) | ||
| Electric charge (2) | ||
| Charge separation |
Find energy relative to infinite separation.
Compare interaction energies at different separations.
Find the interaction energy of +2.00 µC and +3.00 µC point charges separated by 0.500 m in vacuum.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Assumptions
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