From: Andrew Lorimer Date: Mon, 3 Sep 2018 12:24:54 +0000 (+1000) Subject: Merge: forgot some shit again X-Git-Tag: yr11~52 X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/0cb32768913b3f13443e051225442760e4ebc781?ds=inline;hp=-c Merge: forgot some shit again --- 0cb32768913b3f13443e051225442760e4ebc781 diff --combined physics/light-matter.md index a2d5f6d,6630fd3..ce114ba --- a/physics/light-matter.md +++ b/physics/light-matter.md @@@ -46,7 -46,6 +46,7 @@@ particle model - rate of photoelectron release is proportional to intensity of incident light - shining light on a metal "bombards" it with photons - no time delay +- one photon releases one electron #### Work function and threshold frequency @@@ -69,13 -68,9 +69,13 @@@ $f$ is frequency of incident photon (** $\phi$ is work function ("latent" energy) Gradient of a frequency-energy graph is equal to $h$ -y-intercept is equal to $\phi$ +y-intercept is equal to $\phi$ +voltage $V$ in circuit is indicative of max kinetic energy in eV #### Stopping potential $V_0$ + +Smallest voltage to achieve minimum current + $$V_0 = {E_{K \operatorname{max}} \over q_e} = {{hf - \phi} \over q_e}$$ ## Wave-particle duality @@@ -110,7 -105,8 +110,8 @@@ $$\rho = {hf \over c} = {h \over \lambd ### Absorption - - Black lines in spectrum show light not reflected + - Black lines in spectrum show light not reflected + - Frequency of a photon emitted or absorbed can be calculated from energy difference: $E_2 – E_1 = hf$ or $= hc$ ### Emission @@@ -171,6 -167,17 +172,17 @@@ Therefore, position and velocity canno **Quantum mechanical model** - electron clouds rather than discrete shells (electrons are not particlces). We can only calculate probability of an electron being observed at a particular position + Newton's and Einsteins models work together + + ### Photon-electron interaction + + When a photon collides with an electron, momentum is transferred to electron. + + $$\rho_{\text{photon}}={h \over \lambda}$$ + $$E=\rho c$$ + + + 774 abc melbourne