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Physics 30 IB Chapter 17
Transcript of Physics 30 IB Chapter 17
Option D The Quantum Theory Electrons (-)
Neutrons (No charge) Fundamental Particle? Cannot be divided into a smaller particle; elementary particles Anti-matter Opposite charge to ordinary matter Same mass All particles have the corresponding anti-particles A collision between a partciles and its anti-particle will annilate both -> creates a pair of high-energy GAMMA RAY PHOTONS in OPPOSITE directions COLLISION Particle A Anti-Particle A ~ BOOM ~
Both are annilated EQUALS!! Gamma Ray Photon Gamma Ray Photon Gamma Ray Photon Gamma Ray Photon Picture Example: Electron + Positron -> 2 Gamma Ray
e- + e+ -> 2y Particle -- Antiparticle
Electron -- Position
Proton -- Antiproton
Neutron -- Antineutron
Neutrino -- Antineutrino Cloud Chamber? -Contains dust-free air supersaturated with vapour from a liquid, like water or ethanol.
- A DEVICE that uses trails of droplets of CONDENSED VAPOUR to show the PATH of charged particles Bubble chamber? - devloped in 1952 by Donald Glaser
- uses liquefied gas; lowering pressure = lower boiling point
- A DEVICE that uses trails of bubbles in a SUPERHEATED LIQUID to show the PATHS of charged particles Tracks of subatomic particles from a bubble chamber
- Heavier partciles have straighter tracks Example 17.1 - page 833 Tracks made particles moving at a speed of 0.10c through a uniform magnetic field of 30 mT. Initial radius is 5.7 mm. DETERMINE the charge-to-mass ratio for hte particles. Givens:
v = 0.10c -> 3.0 x 10^7 m/s
|B| = 30 mT -> 0.030 T
r = 5.7 mm -> 0.0057 m Finding: q/m Note:
-Apply the RIGHT-HAND RULE, shows the particle spiraling CLOCKWISE has a POSITIVE CHARGE. Vice-versa
- No track beforehand = they originated from photon or neutral particle. Charge must be conserved, net charge must be zero. THUS both particles are equal but have opposite charges. |Fm| = |Fc|
|B|qv = mvv/r
|B|q = mv/r
q/m = v/|B|r B/c q, v, r, and |B| are the same, m must be the same for both particles Substitute:
q = 3.0 x 10^7 m/s
m = 0.030 T x 0.0057 m Telsa is a derived unit.
1 T = 1 kg/As^2 q = 3.0 x 10^7 m/s
m = 0.030 kg/As^2 x 0.0057 m = 1.60 x 10^-19 C
9.11 x 10^-31 kg Terms:
- Quantum Field Theory: a Field theory developed using both QUANTUM MECHANICS and RELATIVELY THEORY.
Mediating Particle: a Virtual particle that carries one of the fundamental forces.
Virtual Particle: A particle that exists for a such SHORT time that is NOT DETECTABLE.
Quantum Electrodynamics: Quantum field theory dealing with the INTERACTIONS of electromagnetic fields, charge particles, and photon.
Gluon: the Mediating Particle for STRONG NUCLEAR FORCES
Graviton: the HYPOTHETICAL mediating particle for the gravitational force.
SEE Table 17.1 in separate notes The Pauli Exclusion Principle? - it is fundamental to the way that particles interact
- 2 or more e- repel each other b/c they CANNOT OCCUPY the SAME QUANTUM STATE at the same time. Photons are different. WHY? B/c of the particles' spin
See Table 17.2 Only Fermions obey the principle, Photons (Bossons) don't obey it b/c they have Spin 1 More Terms:
Primary Cosmic Rays: High energy particles that flow from space into Earth's atmosphere
Secondary Cosmic Rays: the shower of particles created by the COLLISION between primary cosmic rays and atoms in the atmosphere
Van de Graaff: Moving belt transfer charm to a hollow, conductive sphere, building POTENTIAL DIFFERENCE, then propels ions through a accelerator chamber
Drift Tube: Charged particles accelerated through a series of electriodes.
Cyclotron: A magnetic field perpendiclar to the paths of the charge particles make them follow circular paths. the Radisu of each particl's path increase with its speed.
Synchrotron: Advanced cyclotron. Increases the strength of the magnetic field as particle's energy increases. So particles travel in a circl, than spiraling outward, Elementary Particles? - Cannot be broken down
- No Internal structure
They are Leptons, Quarks, and Exchange particles Hadron vs. Lepton
subatomic particles that DOES interact via the strong nuclear force
ie. protons & netrons (and antiparticles) Lepton
subatomic particles that DOES NOT interact via the strong nuclear force
ie. Electrons & Neutrino (and antiparticles) Exchange Particle? 1933, Yukawa's theory. "Every force is due to the exchange of a particle." ->LiNkS electromagnetic force with the Photon The MAGNITUDE of the force is dependent of the amount of photons b/w the two aprticles. As they SPREAD out, the particle receives LESS photons
#photons -> F Energy and Mass of exchange particles See Calculations 17.1 & 17.2
And Table 17.3 Baryons - 3 Quarks
Proton & Neutron
Mesons - 2 Quarks
Pion Original Particle Recieving Particle After n years Original Particle Recieving Particle After a(x) years Quantum Numbers and Conservation ie.:
288 222 4
. Ra -> Rn + He
'88 86 2 Charge: +88 86 + 2 = +88
Mass: 226 222 + 4 = 226 See Tables:
Table 17.8 Quarks and the Standard Model See Table 17.9 Baryons(Bosson): 1 1/2 or 1/2 Spin
Messon(Fermion): 0 or 1 Spin Strangeness:
Some particles do not interact as predicted by the conservation of charge and baryon numbers.
Strangeness = #antiquark strange - #quark strange Properties of Quarks Quark Confinement:
Free(single) quarks not yet detected
Exist only confiened inside other particles
As two quarks separate, the energy transfers grows and become great enough to create ANOTHER one, -> meson Gluons:The Exchange particle
The STRONG FORCE is the force between quarks For Strong force, there are three types of charges: Red Blue, Green.
Antiquarks have anti-red,anti-blue, or anti-green All particles are white. RGB -> White
Baryons MUST have one red, blue, and green.
Mesons MUst one only colour and the anti-colour Gluons have two colours, they can cancel each other out thus having colour change. Feyman Diagrams Quarks u d s c t b Leptons Ve e Vu u t Vt Possible Interactions They are only a REPRESTATION
The Vertex is always made up of two particles and the exchange particle
Leptons and quarks CANNOT be on the same diagram
Time progresses left to right
When the arrow is going right to left, it signifies that it is an antiquark. See Diagrams Examples: DIANE MARIE SANTOS
PHYSICS 30-1 IB
2011 DIANE MARIE SANTOS
PHYSICS 30-1 IB