22.1.4—The electronvolt (eV) as a unit of energy
- Syllabus
- 9702–2028–2029
- Objective
- 22.1.4
- Level
- A2
An electronvolt is the energy gained by one elementary charge through one volt
One electronvolt is 1 eV=1.60×10⁻¹⁹ J, the energy transfer when a charge of magnitude e moves through 1 V.
Use eV for particle-scale energies and convert to joules when applying SI equations or comparing macroscopic work.
A 5.0 eV electron has energy about 8.0×10⁻¹⁹ J.
An electronvolt is an energy unit, not a voltage or an electron’s mass.
ConceptA-Level CAIE Physics A2