WaveParticle Duality Question What happens if we repeat

Wave/Particle Duality

Question: What happens if we repeat Young’s double slit experiment with a beam of electrons (particles) instead of light? • Answer: We still get an interference pattern!! • Why? All particles exhibit “wave-like” properties!!!!!

De. Broglie Wavelength λ = h/p h = 6. 63 x 10 -34 J*s • What is the De. Broglie wavelength of an electron moving at v = 3. 5 x 106?

What is the De. Broglie wavelength of a baseball (m = 0. 15 kg) moving at v = 13 m/s?

Question: If particles can act like waves can waves act like particles? • Answer: Yes!!!! (Photo. Electric effect, Compton Scattering)

Photoelectric Effect • Einstein won his Nobel prize for it. He realized that light is made up of packets of energy (photons) • When light shines on a metal surface it can eject electrons from the metal, but only if the frequency is high enough. • Higher frequency means higher energy per photon. E=hf

Photoelectric Effect hf = k Emax + Wo • Each photon emits one electron • Higher frequency means the electron is emitted with more KE (velocity). • If the minimum frequency is used KE = 0. • Higher Intensity means more overall energy but if the frequency is not great enough no electrons are ejected. • Higher intensity means more photons which can eject more electrons, but can’t give individual electrons more energy.

What is the work function of a metal that requires a min. wavelength of 485 nm to eject electrons from its surface?

What is the velocity of an electron ejected by light of frequency 1. 5 x 1015 Hz from a metal with a work function 4. 1 x 10 -19 J?