vid 2 photoelectric effect and particle light

blackbody

perfect absorber and emitter

everything at a temperature emits radiation with _ , just shifted to a _ wavelength as things get warmer

same shape curve, shorter

ultraviolet catastrophe

theoretical models showed discrepancies at shorter wavelengths - intensity became infinitely large as wavelength became smaller

planck theorized that

energy assumed certain, quantized values related to frequency

planck’s equation

E = nh(nu)

classical theory of photoelectric effect (wrong)

if frequency increases, so does the number of electrons with no relationship between frequency and KE of electrons

observed photoelectric effect

at lowest frequency (regardless of intensity) no electrons ejected, but as it increases they are, with no increase in number after certain frequency

threshold frequency (nu₀)

must be reached to eject electrons, differing by metal

what did Einstein say

energy of light is being absorbed by electron and used to eject, with any leftover going to KE

E_photon = KE_electron + phi

h(nu) = ½ m_eu² + h(nu₀)