Electron-volt to Joule Converter

Popular Energy Converters:

Electron-volt to Joule: The Essentials

electron-volt to joule metric conversion table

How to Convert EV to J (Electron-volt to Joule)?

We can convert electron-volt to joule by using an example.

How to Convert Electron-Volts to Joules (Step-by-Step)

The electron-volt (eV) is the standard energy unit in particle physics, quantum mechanics, and semiconductor physics. The conversion factor is 1 eV = 1.602 × 10⁻¹⁹ J (the elementary charge in coulombs). This tiny unit is perfect for atomic-scale energies.

1. Identify the energy value in electron-volts (eV, keV, MeV, or GeV).
2. Multiply by 1.602 × 10⁻¹⁹ to convert to joules.
3. If using keV, MeV, or GeV, first convert to eV: 1 keV = 10³ eV, 1 MeV = 10⁶ eV, 1 GeV = 10⁹ eV.
4. Express the result in appropriate SI prefix (fJ, pJ, nJ, etc.).

Common eV to Joules Conversions

Reference values spanning particle physics, chemistry, and photon energies, showing the eV-to-joule relationship at different scales.

Solved Examples: eV to Joules

Practice: eV to Joules

Try solving these on your own to test your understanding:

1. Convert 2.5 eV (blue-green photon) to joules. (Answer: 4.005 × 10⁻¹⁹ J)
2. The work function of gold is 5.1 eV. Express in joules. (Answer: 8.17 × 10⁻¹⁹ J)
3. Convert 100 keV (X-ray) to joules. (Answer: 1.602 × 10⁻¹⁴ J)
4. A gamma ray has 2.5 MeV. Express in joules. (Answer: 4.005 × 10⁻¹³ J)
5. Convert 0.025 eV (thermal energy at room temperature) to joules. (Answer: 4.005 × 10⁻²¹ J)

Semiconductor Band Gaps in eV

Semiconductor physics uses eV exclusively for band gaps, which determine the wavelengths of light a material can absorb or emit. Key values: Silicon (Si): 1.12 eV — the foundation of solar cells and computer chips. Gallium Arsenide (GaAs): 1.42 eV — used in high-efficiency solar cells and LEDs. Gallium Nitride (GaN): 3.4 eV — blue LEDs and power electronics. Diamond: 5.5 eV — ultrawide-gap insulator. Converting to joules helps calculate photon wavelengths via E = hc/λ.

Photon Energy and Light

The energy of a photon equals hf = hc/λ, where h = 4.136 × 10⁻¹⁵ eV·s. Visible light spans 1.65–3.1 eV: Red (700 nm) = 1.77 eV = 2.84 × 10⁻¹⁹ J. Green (550 nm) = 2.25 eV = 3.61 × 10⁻¹⁹ J. Violet (400 nm) = 3.1 eV = 4.97 × 10⁻¹⁹ J. UV starts above 3.1 eV, X-rays at ~100 eV, and gamma rays above 100 keV. The eV-to-joules conversion connects quantum optics with classical energy measurements.

Particle Physics: Mass-Energy Equivalence

In particle physics, mass is expressed in eV/c² (using E = mc²). Electron mass: 0.511 MeV/c² = 8.19 × 10⁻¹⁴ J. Proton mass: 938.3 MeV/c² = 1.50 × 10⁻¹⁰ J. Higgs boson: 125.1 GeV/c² = 2.00 × 10⁻⁸ J. The LHC collision energy of 13 TeV (per beam) = 2.08 × 10⁻⁶ J — about the kinetic energy of a mosquito in flight, concentrated into a single subatomic particle.

Key Takeaways

• Multiply eV by 1.602 × 10⁻¹⁹ to get joules.
• 1 eV is the energy gained by one electron through 1 volt potential difference.
• Prefixes: keV (×10³), MeV (×10⁶), GeV (×10⁹), TeV (×10¹²).
• Visible light photons: 1.65–3.1 eV; silicon band gap: 1.12 eV.
• Proton rest mass energy: 938.3 MeV = 1.50 × 10⁻¹⁰ J.
• LHC beam energy (6.5 TeV per proton) ≈ 1 microjoule — a mosquito in flight.

Electron-volt to Joule Conversion Formula

Frequently Asked Questions