Momentum Of Electromagnetic Radiation Complete Absorption
Momentum Of Electromagnetic Radiation Complete Absorption — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Momentum of Electromagnetic Radiation (Complete Absorption) Applicable when electromagnetic waves are incident on a surface and are completely absorbed. Energy of a photon is E = hf Momentum of a photon is p photon = h / lambda Substitute lambda = c / f to get p photon = hf / c Since E = hf, then p photon = E / c Summing over all photons: p = U / c Surface must be perfectly absorbing (black body) Incident radiation must be normal to the surface for direct application Thinking momentum is zero because photons are massless. Using this formula for perfectly reflecting surfaces (where momentum delivered is 2U/c). Confusing total energy U with Intensity I.