- summary_type: application
- word_count: 160
Three key comparisons between a photon and an electron: (1) Same energy E: λ_photon = hc/E >> λ_electron = h/√(2mE). The photon has a much longer wavelength (ratio ~1000 at eV energies). (2) Same momentum p: both have the same wavelength λ = h/p. But E_photon = pc >> E_electron = /(2m). The photon has vastly more energy. (3) Same wavelength λ: both have the same momentum. E_photon/E_electron = 2mcλ/h >> 1. Again the photon has more energy. These comparisons are frequently tested in JEE as conceptual MCQs. The key insight: the photon's linear E-p relation (E = pc) versus the electron's quadratic relation (E = /2m) causes the differences. At the same wavelength, the photon always has more energy. At the same energy, the photon always has a longer wavelength.