Photon
| Formula / Notation | E = hν = hc/λ; photon energy at λ = 500 nm: ~4 × 10⁻¹⁹ J (2.5 eV) |
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| Also Known As | Light quantum, photon particle, EM radiation quantum, light particle |
What is Photon?
The quantum of electromagnetic radiation, carrying energy E = hν, where h is Planck's constant and ν is frequency. Photons have zero rest mass and travel at the speed of light. In atomic spectroscopy, photons are emitted or absorbed when electrons change energy levels.
Formula & Notation
Other Names / Synonyms: Light quantum, photon particle, EM radiation quantum, light particle
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The quantum of electromagnetic radiation, carrying energy E = hν, where h is Planck's constant and ν is frequency. Photons have zero rest mass and travel at the speed of light. In atomic spectroscopy, photons are emitted or absorbed when electrons change energy levels.
Photons are used in: spectroscopy (absorption, emission, Raman, fluorescence), photovoltaics (solar cells convert photons to electrical energy), photocatalysis (TiO₂ + UV photons generate reactive oxygen species), laser technology (stimulated emission produces monochromatic photons), and medical ima…
High-energy photons (UV: >3.1 eV, X-ray, gamma) are ionising radiation causing DNA damage, cataracts, and cancer. UV photons require protective eyewear and enclosures. X-ray and gamma sources require lead shielding, dosimetry, and regulatory licensing. Near-IR and microwave photons cause tissue heat…
The formula or notation for Photon is: E = hν = hc/λ; photon energy at λ = 500 nm: ~4 × 10⁻¹⁹ J (2.5 eV)