A photon with a wavelength of 2 A photon with a wavelength of 2.29 × 10–7 meter strikes a mercury atom in the ground state. Calculate the energy, in joules, of this photon. [Show all work, including the equation and substitution with units.] [2] Determine the energy, in electronvolts, of this photon. [1] Based on your answer to the previous question, state if this photon can be absorbed by the mercury atom. Explain your answer. [1]

THE FUNDAMENTAL PARTICLES OF ALL MATTER THE STANDARD MODEL THE FUNDAMENTAL PARTICLES OF ALL MATTER

BASIC DEFINITIONS FUNDAMENTAL: Most basic unit; particle which cannot be subdivided any further we now think that protons and neutrons can be broken down even further…protons and neutrons are not fundamental

SO WHAT ARE THE FUNDAMENTAL PARTICLES? 6 QUARKS 6 ANTIQUARKS 6 LEPTONS 6 ANTILEPTONS FORCE CARRIER PARTICLES

BARYONS Made up of 3 quarks Are examples of Hadrons There are 6 types of quarks quarks have fractions of electron charge: -(1/3)e, +(2/3)e have interesting names…see right

EXAMPLE OF BARYONS Two common examples of Baryons are the proton and the neutron (remember, must contain 3 quarks) The Proton: (Has a charge of +1) so could contain: u,u,d = (+2/3)e+(+2/3)e+(-1/3)e=+1e The Neutron (Has a charge of 0) d,d,u = (-1/3)e+(-1/3)e+(2/3)e = 0e

EVERY PARTICLE HAS AN ANTIPARTICLE An antiparticle has the same mass as its particle, just a charge that is opposite Examples: proton particle has an antiparticle called the antiproton What are the fundamental particles that make up antiparticles? Remember they are still baryons, so they must still contain 3 quarks (see previous example)

ANTIPARTICLE EXAMPLE Previous example: Antiparticle Example: The Proton: (Has a charge of +1e) so could contain: u,u,d = (+2/3)e+(+2/3)e+(-1/3)e=+1e Antiparticle Example: The Antiproton: (Has a charge of -1e) so could contain: antiup, antiup, antidown OR

ANTIPARTICLE EXAMPLE CONTINUED note the bar over the quark signifies antiquark…. meaning same mass , but opposite charge

EVIDENCE OF ANTIMATTER PAIR PRODUCTION A Photon can spontaneously turn into a particle & an antiparticle cloud chamber paths shows 2 particles emerging as if from nowhere, deflecting in opposite directions in a magnetic field PAIR ANNIHILATION When a particle and an antiparticle meet they disappear being replaced by a photon

Pair Production - Particle Annihilation & E = mc2 Find the mass of each particle produced when a 3.006 x 10-10 J photon disappears ANSWER: 1.67 X 10-27kg Find the energy of the photon produced by the annihilation of an electron and anti-electron particle pair: ANSWER: 1.64 x 10-13J

MESONS Contain 1 quark & 1 antiquark Are another example of a hadron Are very unstable (meaning it falls apart easily and quickly) Examples: A Pion (+)….which acts as a force carrier contains an up quark and a down antiquark An Antipion (-) this is an example of an antiparticle of a meson the antipion contains a down quark and an up antiquark

LEPTONS (the other type of matter) They are fundamental particles they either have a whole number of charge or none at all most common example of a charged lepton: “Electron” Muon and tau have more mass than the electron most common example of an uncharged lepton: “Neutrinos” very little mass very hard to find three types named for their corresponding charged lepton

LEPTONS HAVE ANTIPARTICLES TOO ANTILEPTON EXAMPLE: POSITRON Same mass as an electron, but opposite charge

HEAVY LEPTONS ARE VERY UNCOMMON This is because the meson and tau leptons decay very quickly into lighter leptons LEPTONS DECAY INTO THE FOLLOWING: its corresponding neutrino + quark & antiquark OR b)lepton & antineutrino

EXAMPLE OF LEPTON DECAY QUESTION: What does a muon decay into? 1 POSSIBILITY: Its corresponding neutrino = muon neutrino A new lighter lepton = an electron + The lighter lepton’s antineutrino = an electron antineutrino

FORCE CARRIER PARTICLES A force is created by an exchange of particles between matter The particles exchanged depend on the force. All natural forces are listed below from strongest to weakest Strong Nuclear Force (Strongest) Electromagnetic Force Weak Nuclear Force Gravity (Weakest)

THE STRONG FORCE EXCHANGE PARTICLE = GLUONS mass = 0.1GeV/c2 Force which keeps nucleus together Strong over short ranges

THE ELECTROMAGNETIC FORCE EXCHANGE PARTICLE = PHOTON Examples: Coulomb Force, magnetic force Force is attractive or repulsive

THE WEAK INTERACTION FORCE EXCHANGE PARTICLES = BOSONS (W AND Z) Involved in nuclear decay, fusion of the sun, conversion of neutrons to protons in the nuclei

GRAVITY EXCHANGE PARTICLE = GRAVITON (not yet detected) Always attractive Very weak