Photon Momentum
Photons carry momentum despite having no rest mass. This is key to understanding radiation pressure and Compton scattering.
Variables
Derivation
From E = pc for massless particles and E = hc/λ for photons.
Your notes
Constants in this formula
Check value
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- h = 6.626 070 15 × 10⁻³⁴ J·s (Planck constant)
- λ = 2 m (Wavelength)
Result: p = 3.313035 × 10⁻³⁴ kg·m/s
Other modern physics formulas with the same quantities
- Photoelectric Effect (Quantum Mechanics) shares Planck constant
- Stopping Potential (Quantum Mechanics) shares Planck constant
- Particle in a Box Energy Levels (Quantum Mechanics) shares Planck constant
- Photoelectric Threshold Frequency (Quantum Mechanics) shares Planck constant
- Bragg's Law (Quantum Mechanics) shares Wavelength
- Electron Wavelength (Accelerated) (Quantum Mechanics) shares Planck constant
Where this formula is listed
- Modern Physics formulas, under Quantum Mechanics, alongside Heisenberg Uncertainty Principle, Energy-Time Uncertainty, Time-Dependent Schrödinger Equation and Fermi Energy.
- In the modern physics list it comes after Compton Scattering and before Fermi Energy.
- Modern Physics formula sheet, one of 41 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Photon Momentum formula?
Photon Momentum is written p = h/λ = E/c. Photons carry momentum despite having no rest mass. This is key to understanding radiation pressure and Compton scattering. It belongs to Modern Physics, under Quantum Mechanics.
What are the units in p = h/λ = E/c?
In SI units, p is photon momentum, measured in kg·m/s; h is planck constant, measured in J·s; λ is wavelength, measured in m; E is photon energy, measured in J; c is speed of light, measured in m/s.
How is the Photon Momentum formula derived?
From E = pc for massless particles and E = hc/λ for photons. The result is p = h/λ = E/c.