Electric potential, voltage and potential energy
Voltage is energy change per unit charge.
Key knowledge
In electrostatics, potential difference V_B−V_A is the potential-energy change of a small fixed test charge divided by that signed charge: ΔU=qΔV. Equivalently ΔV=−∫_A^B E·dr and E=−∇V. Potential has an arbitrary additive reference, while differences determine work. A volt is a joule per coulomb; voltage is not itself stored energy.
Values and equations
ΔU=q(V_B−V_A); V_B−V_A=−∫_A^B E·dr; E=−∇V
- U,ΔU
- Electrostatic potential energy and its change J
- q
- Signed fixed test charge C
- V,V_A,V_B
- Potential and endpoint values V
- E
- Electric field V m⁻¹
- r
- Position m
Conditions and scope
- Static electric field with a single-valued potential in the stated domain; a test charge small enough not to change the source configuration.
- For time-varying magnetic fields the electric field can have a nonconservative part; the general potential representation includes −∂A/∂t and a measured loop emf need not be a scalar endpoint difference.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Samuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)2 sources
- University Physics Volume 2, §7.2: electric potential and potential differenceSamuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)Textbook chapter
- University Physics Volume 2, §7.4: determining field from potentialSamuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)Textbook chapter
Evidence and review
Read §7.2 voltage/potential-energy definitions7.1–7.3 and §7.4 field-gradient7.15. Time-dependent limitation directly reuses the already reviewed general potential record; do not equate scalar voltage with arbitrary induction-loop work.
2026-10-10 · /root/audit_life_earth_chemistry — independent Chemistry/Life/Earth editor. Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.
Entry details
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- foundation-physics-electric-potential
- Revision
- foundations-refresh.1
- Structured reference record
- Foundational reference additions