Comparison Note — Photoelectric Effect vs de Broglie Concept — Notes

Feature	Photoelectric Effect (Light as Particle)	de Broglie Hypothesis (Matter as Wave)
Core idea	Light (EM wave) behaves as particles (photons)	Moving particles (electrons, protons) behave as waves
Proposed by	Einstein (1905) — Nobel Prize 1921	de Broglie (1924) — Nobel Prize 1929
Key equation	E = hν; $KE_{max}$ = hν − φ	λ = $\frac{h}{mv}$ = $\frac{h}{p}$
Experimental evidence	Hertz (1887), Lenard (observations); Einstein (theory)	Davisson-Germer (1927) — electron diffraction
What quantity is quantised?	Energy of light (photon carries E = hν)	Momentum of particle (p = h/λ)
Effect of intensity	More photons → higher photocurrent; no effect on $KE_{max}$	More particles → more diffraction intensity; no effect on λ
Effect of frequency/velocity	Higher ν → higher photon energy and $KE_{max}$	Higher v → shorter λ (λ = $\frac{h}{mv}$ )
Role of Planck's constant h	h links frequency to photon energy: E = hν	h links momentum to wavelength: λ = $\frac{h}{p}$
Real-world application	Solar cells, photodiodes, photoelectron spectroscopy	Electron microscope (λ_e << λ_visible → higher resolution)
Particle wave?	Photon IS the particle of light	Electron IS the particle; wave is associated/matter wave
Mass of quanta	Photon: rest mass = 0	Electron: $m_e$ = $9.1 \times 10^{-31}$ kg (has rest mass)