physics·NCERT Class 12·Dual Nature of Radiation
Photoelectric Effect
Medium+80 XP
Shine UV light on a metal and electrons fly off — but bright red light does NOTHING. It's not about brightness; it's about frequency. Einstein's Nobel Prize explains why.
›Einstein's equation: KE_max = hν − φ (φ = work function).
›Threshold frequency ν₀ = φ/h; no emission below ν₀.