modern physics introduction to examine the fundamental nuclear model to examine nuclear...
TRANSCRIPT
Modern Physics
IntroductionTo examine the fundamental nuclear model
To examine nuclear classification
To examine nuclear fission and fusion
Detection Devices
Geiger counter
Scintillation counter
Cloud chamber
Bubble chamber
Superheated liquid
Fundamental Particles
Democritus introduced the word which in English translates as atom Elementary Particles The name given to protons, neutrons and
electrons
Today we use the term "fundamental" for the six types of quarks and the six leptons
Classification of MatterHadrons: Particles made of quarks. Protons, Neutrons and their Anti-particles
Leptons: Are NOT made of sub particles. Electrons are examples of Leptons
Hadrons are further broken into Baryons and Mesons. ( both break down into Quarks)
HadronsHadrons break down into two groupsBaryons are made of 3 Quarks Mesons made up of 2 quarks and
anti-quarks***(must add up to an integer not a
fraction)
Leptons
Leptons are fundamental particles that have no strong interactions
Lepton is Greek for "light particle”
electron there are heavier leptons, of which the first to be found was the muon
The TAU is 12th (quarks + leptons) fundamental building blocks of all matter.
Quarks
Quarks are fundamental matter particles that are constituents of neutrons and protons and other hadrons
Proton -- composed of two Quarks up quarks and a down quark
Sample Problem
A Baryon may have a charge of -1/3e0e+2/3e+4/3e
Correct answer is 0e (all types of matter must have an integer charge)
Scale of nature
Particles are classified by size and charge
Forces give all matter their characteristics and properties
Neutrinos (type of Lepton)
These particles are so small that they pass right through the Earth with interacting with a single atom!!!
Four fundamental interactions
Force : the effect on particle due to another particle
Interaction: the forces and decays which affect a given particle
Strong Force
Quarks and Gluons have a type of charge that is NOT electromagnetic
The “color” charged particles are very powerful (STRONG)
Quarks are glued together with GLUONS (Nuclear Energy)
Weak Force
The stable matter of the universe is made up of the two least massive quarks: UP and Down and the least massive Lepton, the electron ( A Hydrogen Atom)
When a quark or lepton changes type (muons changing to an electron) is called a “flavor” weak interaction
The components of the nucleus are called nucleons.
The two principle nucleons are the proton with a charge of +1e and the neutron which is uncharged.
All atomic nuclei (nuclides) and their components may be represented by the symbol below.
X is the name of the particle
A is the mass #
Z is the atomic #
XAZ XAZ
XAZ
Chemistry Symbols
Isotopes
Nuclei that have the same atomic number, but different mass numbers.
Hydrogen Deuterium Tritium
Nuclear Reaction
Represented by a balanced nuclear equation
HeCHN 42
126
11
157
Nuclear Fission & Fusion
Fission is the chain reaction splitting of an atom
Fusion is the joining of light nuclei to form a heavier more stable nuclei
Reference Chart : Standard Model
Reference Chart
Reference Chart Equations
Ephoton = hf = hc/wavelength
Ephoton = Ei – Ef
E = mc2
All equations calculate the amount of energy in units of eV or J. The conversion is based on the energy of a single electron or mass
Sample Problem
Calculate the energy of the photon that is emitted when a hydrogen atom changes from energy level n=3 to 2
Ephoton = Ei – Ef
= (-3.40 eV) – (-1.51 eV)
= - 1.89 eV
Sample Problem
What is the Radiant energy of a beam of light whose frequency is 5.0 x 1014 Hz
Ephoton = hf = hc/wavelength
= 6.6 x 10-34 J*s (5.0 x 1014 Hz)
= 33 x 10 -20 J
SummaryAtomic Particles are composed of sub-nuclear particles
The nucleus is a conglomeration of Quarks which manifest as Protons and neutrons
Each elementary particle has a corresponding anti-particle
The fundamental source of energy is the conversion of mass into energy