Watts to Electron Volts Converter
Convert energy between watt-based units and electron volts
Please provide a value below to convert between watt-based energy units and electron volts, or vice versa.
What is an Electron Volt?
An electron volt (eV) is a unit of energy equal to the energy gained by a single electron when it moves through an electrical potential difference of one volt. 1 eV = 1.602176634 × 10⁻¹⁹ joules. The electron volt is commonly used in particle physics, quantum mechanics, and semiconductor physics because the energies involved are extremely small when expressed in joules.
Relationship Between Watts and Electron Volts
Watts measure power (energy per unit time), while electron volts measure energy. A watt-second (W·s) equals one joule (J), making it the bridge between the two systems. Since 1 J = 6.241509074461 × 10¹⁸ eV, converting from watt-seconds to electron volts involves multiplying by this constant. For watt-hours, first multiply by 3,600 to convert to joules, then multiply by the eV conversion factor.
Key Conversion Factor
Conversion Formulas
The mathematical relationships for energy conversion
Watt-second to eV
E(eV) = E(W·s) × 6.241509074461 × 10¹⁸ Watt-hour to eV
E(eV) = E(Wh) × 3,600 × 6.241509074461 × 10¹⁸ kWh to eV
E(eV) = E(kWh) × 3,600,000 × 6.241509074461 × 10¹⁸ eV to Watt-second
E(W·s) = E(eV) × 1.602176634 × 10⁻¹⁹ Applications of Electron Volts
Where electron volts are used in science and engineering
Particle Physics
Particle accelerators measure collision energies in GeV (giga electron volts) and TeV (tera electron volts). The Large Hadron Collider operates at 13 TeV.
Semiconductor Physics
Band gap energies in semiconductors are measured in eV. Silicon has a band gap of 1.12 eV, which determines its electrical properties.
X-ray & Medical Imaging
X-ray photon energies are measured in keV (kilo electron volts). Medical X-rays typically use 20–150 keV photons.
Quantum Mechanics
Atomic and molecular energy levels are described in eV. The ionization energy of hydrogen is 13.6 eV.
Watts to Electron Volts Conversion Table
Quick reference for common energy conversions
Watt-second [W·s] to Electron-volt [eV]
| Watt-second [W·s] | Electron-volt [eV] |
|---|---|
| 0.001 W·s | 6.241509e+15 eV |
| 0.01 W·s | 6.241509e+16 eV |
| 0.1 W·s | 6.241509e+17 eV |
| 1 W·s | 6.241509e+18 eV |
| 10 W·s | 6.241509e+19 eV |
| 100 W·s | 6.241509e+20 eV |
| 1000 W·s | 6.241509e+21 eV |
| 10000 W·s | 6.241509e+22 eV |
Watt-hour [Wh] to Electron-volt [eV]
| Watt-hour [Wh] | Electron-volt [eV] |
|---|---|
| 0.001 Wh | 2.246943e+19 eV |
| 0.01 Wh | 2.246943e+20 eV |
| 0.1 Wh | 2.246943e+21 eV |
| 1 Wh | 2.246943e+22 eV |
| 10 Wh | 2.246943e+23 eV |
| 100 Wh | 2.246943e+24 eV |
| 1000 Wh | 2.246943e+25 eV |
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Frequently Asked Questions
What is the conversion factor from joules to electron volts?
1 joule = 6.241509074461 × 10¹⁸ electron volts (eV). Conversely, 1 eV = 1.602176634 × 10⁻¹⁹ joules. This conversion factor is based on the elementary charge of an electron.
How do I convert watt-hours to electron volts?
First convert watt-hours to joules by multiplying by 3,600 (since 1 Wh = 3,600 J). Then multiply by 6.241509074461 × 10¹⁸ to get electron volts. Formula: E(eV) = E(Wh) × 3,600 × 6.241509074461 × 10¹⁸ = E(Wh) × 2.246943×10²² eV.
Is a watt-second the same as a joule?
Yes. A watt-second (W·s) is exactly equal to one joule (J). Both measure the same quantity of energy. 1 W·s = 1 J = 1 V × 1 A × 1 s. This makes watt-seconds the most direct bridge between watt-based units and electron volts.
Why are electron volts used instead of joules?
Electron volts are used in atomic, nuclear, and particle physics because the energies involved are extremely small when expressed in joules. For example, visible light photons have energies of 1.65–3.26 eV, which would be 2.64–5.22 × 10⁻¹⁹ J — awkward numbers to work with.
How many electron volts are in 1 kilowatt-hour?
1 kilowatt-hour (kWh) = 3,600,000 joules = 2.246943 × 10²⁵ electron volts. This is an enormous number because 1 kWh represents a large amount of energy compared to the sub-atomic scale where eV is typically used.
Can I convert electron volts back to watts?
You can convert electron volts to watt-seconds (joules) by multiplying by 1.602176634 × 10⁻¹⁹. To express this as watts, you would need to know the time period over which the energy is transferred: P(W) = E(J) ÷ t(s).
What are keV, MeV, GeV, and TeV?
These are metric prefixes applied to electron volts: keV = 10³ eV (kilo), MeV = 10⁶ eV (mega), GeV = 10⁹ eV (giga), TeV = 10¹² eV (tera). X-rays are measured in keV, nuclear reactions in MeV, and particle collisions in GeV or TeV.
What is the energy of one photon of visible light in electron volts?
Visible light photons range from about 1.65 eV (red, 750 nm) to 3.26 eV (violet, 380 nm). Green light (550 nm) has photon energy of approximately 2.25 eV. These values come from E = hc/λ, where h is Planck's constant and c is the speed of light.