EM radiation Flashcards
Photoelectric effect
shine light, of frequency higher than threshold frequency, onto a metal surface and photo electrons are emitted
stopping potential
Ek= Vs x e
excitation and de-excitation
electron moves up an energy level
when they de-excite they emit the same photon that excited it
ionisation
electron is removed from an atom
energy of each energy level = energy required to ionise from the level
Fluorescent tubes
high voltage applied across mercury vapour
accelerates free electron which ionise some mercury atoms producing more free electrons
free electrons collide with mercury atoms, exciting them
when excited electrons de-excite, UV photons emitted
phosphor coating on tube absorb the particles, exciting its electrons
excited phosphorus electrons de-excite, emitting lower energy photons
wave particle duality
interference and diffraction - wave properties
photoelectric effect - particle properties
de broglie wavelength
λ=h/mv
