What is electronvolt?
An electronvolt is a unit of energy equal to the work done on an electron by a potential difference of one volt, approximately 1.602 × 10⁻¹⁹ joules. It is used in atomic physics, particle physics, and quantum mechanics.
Real-world uses
The electronvolt is the standard energy unit in particle physics, atomic physics, and semiconductor science. X-ray photon energies are measured in keV; visible light photons in eV (about 1.8–3.1 eV); nuclear reactions in MeV; and particle accelerator energies in GeV or TeV.
History
The electronvolt came into use in the early 20th century with the development of quantum mechanics and experimental atomic physics. As physicists began measuring energies of electrons and photons, the eV provided a convenient unit far smaller than the joule but appropriate for subatomic-scale phenomena.
Common mistakes
Confusing the electronvolt with a unit of voltage—it is a unit of energy equal to the kinetic energy gained by one electron accelerated through a potential difference of one volt (1 eV = 1.602 × 10⁻¹⁹ J). Also mixing up the scale prefixes (keV, MeV, GeV, TeV) when discussing different physical phenomena.
What is kilowatt hour?
A kilowatt hour is a unit of energy equal to 1,000 watt hours. It is the standard billing unit used by electricity providers worldwide to measure household and commercial energy consumption.
Real-world uses
The kilowatt-hour is the standard unit for electricity billing worldwide. A typical household uses 250–1,000 kWh per month. EV charging, home appliance energy consumption, and solar panel production are all expressed in kWh. Utility bills list total kWh consumed and price per kWh.
History
The kilowatt-hour became the standard billing unit for electricity in the early 20th century as public electricity grids were established. Its use is mandated for utility metering in most countries. It equals exactly 3,600,000 joules (3.6 MJ).
Common mistakes
Writing "kW/h" instead of "kWh"—the slash implies division (kW per hour), which is a rate of power change, not an energy unit. Also confusing kWh with kW: a 2 kW heater running for 4 hours uses 8 kWh of energy, not 8 kW.
When is this conversion used?
Electricity bills use kilowatt-hours while physics calculations use joules. Converting between them is essential for energy audits, comparing appliance efficiency, and understanding power consumption.
Worked examples
1 electronvolt = 4.450491e-26 kilowatt hour
1 kilowatt hour = 3,600,000 joule
How to convert electronvolt to kilowatt hour
To convert electronvolt to kilowatt hour, multiply the value by 4.450491e-26.
To convert kilowatt hour back to electronvolt, multiply by 2.246943e+25.
Measurement standards
The joule is the SI derived unit of energy, defined as one kilogram-metre-squared per second-squared (kg·m²/s²). The kilowatt-hour, equal to exactly 3.6 megajoules, is accepted for use with the SI by the BIPM for practical electricity metering.
Did you know?
A single bolt of lightning releases roughly 1 to 5 gigajoules of energy, yet only a small fraction reaches the ground as electrical current. Most of the energy dissipates as light, heat, and the thunder shockwave.
Quick reference: electronvolt to kilowatt hour
| electronvolt | kilowatt hour |
|---|---|
| 0.1 | 4.450491e-27 |
| 0.5 | 2.225245e-26 |
| 1 | 4.450491e-26 |
| 2 | 8.900981e-26 |
| 5 | 2.225245e-25 |
| 10 | 4.450491e-25 |
| 25 | 1.112623e-24 |
| 50 | 2.225245e-24 |
| 100 | 4.450491e-24 |
| 250 | 1.112623e-23 |
| 500 | 2.225245e-23 |
| 1,000 | 4.450491e-23 |
Common values
| electronvolt | kilowatt hour | |
|---|---|---|
| A food calorie (1 kcal) | 2.611447e+22 electronvolt | 0.00116222 kilowatt hour |
| A AA battery | 5.842052e+22 electronvolt | 0.0026 kilowatt hour |
| Boiling a kettle | 2.621434e+24 electronvolt | 0.11666667 kilowatt hour |
| Daily human diet (2000 kcal) | 5.222895e+25 electronvolt | 2.32444444 kilowatt hour |
| 1 gallon of gasoline | 8.223812e+26 electronvolt | 36.6 kilowatt hour |
Available Energy units
More electronvolt conversions
- Convert electronvolt to joule
- Convert electronvolt to kilojoule
- Convert electronvolt to kilowatt hour
- Convert electronvolt to calorie (thermochemical)
- Convert electronvolt to kilocalorie (dietary)
- Convert electronvolt to watt hour
- Convert electronvolt to megajoule
- Convert electronvolt to British thermal unit
- Convert electronvolt to therm (US)
Assumption: calorie means thermochemical calorie, and therm means US therm.