Quantum and nuclear physics – Physics notes (ZIMSEC A Level)

Light consists of photons with energy E = hf = hc/λ (h = 6.63 × 10⁻³⁴ J s). Electrons are emitted only if hf exceeds the work function φ: hf = φ + ½mv²max. Intensity changes the number of electrons, not their maximum energy – evidence for the particle nature of light.