5/4 do now – on a new sheet n v

5/4 do now – on a new sheet n v
Sketch a graph that correctly relates the speed of an EM wave in a medium to the index of refraction for that medium. Show work. n v

Modern Physics Wave-Particle Duality of Energy and Matter
Models of Atoms The Nucleus The Standard Model of Particle Physics

1. Wave-Particle Duality of Energy and Matter objectives
Know: Definitions of photon and Planck’s Constant. Understand: The manner in which the Photoelectric Effect demonstrates the particle nature of light. Be able to: Determine the energy of a photon based on its frequency and/or wavelength. Determine a photon’s ‘type’ using the EM Spectrum chart. Use/interpret a graph of photon energy vs. frequency and/or frequency vs. wavelength. Homework – castle learning

Light as a wave Light is an electromagnetic wave produced by an oscillating _______________________. The vibrating charges produce alternating _________________________________which are perpendicular to the direction of the wave’s motion. This waves can travel through vacuum in vast space. Light is a wave because Light have wave characteristics such as _________________________________________________ Light exhibit wave behavior such as _________________________________________________ However, the wave model of light can not explain interactions of light with matter electric charges electric and magnetic fields amplitude, wavelength, frequency, and velocity. diffraction, interference, and the Doppler effect.

Waves have a particle nature
An unusual phenomenon was discovered in the early 1900's. If a beam of light is pointed at the negative end of a pair of charged plates, a current flow is measured. A current is simply a flow of electrons in a metal, such as a wire. Thus, the beam of light must be liberating electrons from one metal plate, which are attracted to the other plate by electrostatic forces. This results in a current flow. Waves have a particle nature An unusual phenomenon was discovered in the early 1900's. Photoelectric_Effect If a beam of light is pointed at the negative end of a pair of charged plates, a current flow is measured which means the beam of light must be liberating electrons from one metal plate, which are attracted to the other plate by electrostatic forces. However, the observed phenomenon was that the current flow varied strongly with the frequency of light such that there was a sharp cutoff and no current flow for smaller frequencies. Only when the frequency is above a certain point (threshold frequency), the current flow increases with light strength. Photoelectric Effect

Einstein explains photoelectric effect
..\..\RealPlayer Downloads\Photoelectric Effect and Photoelectric Cell.flv Einstein successful explained the photoelectric effect within the context of the new physics of the time, quantum physics developed by Max Planck. Quantum theory assumes that electromagnetic energy is emitted from and absorbed by matter in discrete amounts of packets. Each packet carries a quantum of energy. The quantum, or basic unit, of electromagnetic energy is called a photon. A photon is a mass-less particle of light, it carries a quantum of energy. Energy: E = h∙f

Energy: E = h∙f since f = c/λ E = h∙f = h∙c/λ
The amount of energy E of each photon is directly proportional to the frequency f of the electromagnetic radiation, and inversely proportional to the wavelength λ. E is energy of a photon, in Joules, or eV, 1 eV = 1.60x10-19 J h is Planck’s constant, 6.63 x J∙s f is frequency of the photon, in hertz c is the speed of light in vacuum, c = 3.00x108 m/s λ is wavelength, in meters E λ E f Direct relationship Slope = h Inverse relationship

The Compton effect: photon-particle collision
In 1922 Arthur Compton was able to bounce an X-ray photon off an electron. The result was an electron with more kinetic energy than it started with, and an X-ray with less energy than it started with. A photon can actually interact with a particle! A photon has momentum!! - another proof that photon is a particle. During the collision, both energy and momentum are conserved.

The momentum of a photon
A photon, although mass-less, it has momentum as well as energy. All photons travel at the speed of light, c. The momentum of photon is p = h/λ = h∙f/c Where p is momentum, h is plank’s constant, λ is the wavelength Momentum p is directly proportional to the frequency light, and inversely proportional to the wavelength. p = h/λ = h∙f/c E = hc/λ = h∙f

In conclusion, light has both wave and particle nature. Wave nature:
Exhibit wave characteristics: _______________________________________________________ Exhibit wave behavior: _______________________________________________ Particle nature: ________________________________________ _________________________________ wavelength, frequency, crests, troughs, amplitude … interference, diffract, Doppler effect, refract, reflect … Photoelectric effect Interact with electron – has momentum Reflect like a particle

Particles have wave nature
Just as radiation has both wave and particle characteristics, matter in motion has wave as well as particle characteristics. The wavelengths of the waves associated with the motion of ordinary object is too small to be detected. The waves associated with the motion of particles of atomic or subatomic size, such as electrons, can produce diffraction and interference patterns that can be observed. ..\..\RealPlayer Downloads\Double Slit Experiment - The Strangeness Of Quantum Mechanics.flv

All Matters have wave nature
Louis de Broglie (French physicist and a Nobel laureate) assumed that any particle--an electron, an atom, a bowling ball, whatever--had a "wavelength" that was equal to Planck's constant divided by its momentum... λ = h / p ..\..\RealPlayer Downloads\Matter Wave - De Broglie Wavelength.flv

In summary Waves has particle nature, it has momentum just like a particle: Particle has wave nature, it has a wavelength just like a wave: p = h / λ λ = h / p

Example Which graph best represents the relationship between the intensity of light that falls on a photo-emissive surface and the number of photoelectrons that the surface emits? a b c d Note: this only happens when the frequency of the light beam is above a certain point

Example When the source of a dim orange light shines on a photosensitive metal, no photoelectrons are ejected from its surface. What could be done to increase the likelihood of producing photoelectrons? Replace the orange light source with a red light source. Replace the orange light source with a higher frequency light source. Increase the brightness of the orange light source. Increase the angle at which the photons of orange light strike the metal.

Example A beam of monochromatic light incident on a metal surface causes the emission of photoelectrons. The length of time that the surface is illuminated by this beam is varied, but the intensity of the beam is kept constant. Which graph below best represents the relationship between the total number of photoelectrons emitted and the length of time of illumination? a b c d

Class work Worksheet #1, 3, 5-9, 11 Review questions #1-11

5/5 do now In which medium is the wavelength of yellow light the shortest? [show work] Flint glass Crown glass Diamond zircon

2. Models of an Atom objectives
Early models of atoms – notes Objectives Describe ____________________ model Explain the strengths and weaknesses of ____________________________ model of the atom Recognize that each element has a unique _______________ and ____________________ spectrum Explain atomic spectra using ____________________ model of the atom. Thompson’s model About 100 years ago, J. J. ___________________________ discovered that ____________________ are relatively low-mass, negatively charged particles present in atoms. Because atoms are neutral, he proposed a model - the "atom" was made of negatively-charged particles (electrons) dispersed among positively-charged particles (protons) as a “_________________________". . Rutherford’s model In his experiment, He fired alpha particles beam at extremely thin ________________________________. He expected alpha particles travel in _____________________ line unaffected. However, he found some particles were scattered at large _____________________. Rutherford explained this phenomenon with a revitalized model of the atom in which most of the mass was concentrated into a compact ___________________ (holding all of the positive charge), with _________________ occupying the bulk of the atom's space and orbiting the nucleus at a distance In Rutherford’s model of the atom, electrons orbit the ____________ in a manner similar to planets orbiting the sun. Limitations According to Rutherford, electrons ________________ due to centripetal force, and the accelerating charges radiate electromagnetic waves, _______________ energy. So the radius of electron’s orbit would steadily _____________________. This model would lead a rapid ________________________ of the atom as the electron plunged into the nucleus Another problem with Rutherford’s model is as electrons’ kinetic energy decrease, the radiated electromagnetic energy would increase, the electromagnetic spectrum produced should be continuous. This _________________ to the observed bright-line spectrum that is characteristic of each element. 2. Models of an Atom objectives Describe Thompson’s model Explain the strengths and weaknesses of Rutherford’s model of the atom Describe Bohr model of an atom Describe cloud model Explain why only certain energy levels are permitted in atoms. Homework: castle learning Thompson’s model Rutherford’s model

About 440BC, a Greek scientist named Democritus came up with the idea that eventually, all objects could be reduces to a single particle that could not be reduced any further. He called this particle an atom, from the Greek word atomos which meant “not able to be divided.” From this, the idea of the atom – the basic building block of all matter – was born. Around 1700, scientists understanding of molecular composition of matter had grown considerably. They had figured out that elements combine together in specific ratios to form compounds. In 1803, British chemist John Dalton came up with a theory about atoms: All substances are made of small particles that can’t be created, divided, or destroyed called atoms. Atoms of the same element are exactly alike, and atoms of different elements are different from each other. (So, atoms of gold are exactly like gold atoms, but different than aluminum atoms). Atoms join with other atoms to make new substances.

Thompson’s model In 1897, a British scientist named JJ Thomson discovered that electrons are relatively low-mass, negatively charged particles present in atoms. Because atoms are neutral, he proposed a model - the "atom" was made of negatively-charged particles (electrons) dispersed among positively-charged particles (protons) like raisins in "plums in a pudding". In 1909, British scientist Ernest Rutherford decided to test the Thomson theory, and designed an experiment to examine the parts of an atom.

Rutherford’s model In his experiment, He fired alpha particles (2 positive charges) beam at extremely thin gold foil. He expected alpha particles travel in straight line unaffected because the net electric force on the alpha particle would be relatively small. However, he found a small number of particles were scattered at large angles. Rutherford explained this phenomenon by assuming the following: Most particles were not affected due to the vast empty space inside the atom Only a few particles were scattered due to the repulsive force between the concentrated positive charge inside the atom and the particle. Rutherford’s model of the atom most of the mass was concentrated into a compact nucleus (holding all of the positive charge), with electrons occupying the bulk of the atom's space and orbiting the nucleus at a distance.

In Rutherford’s model of the atom, electrons orbit the nucleus in a manner similar to planets orbiting the sun.

Limitation of Rutherford model
According to Rutherford, electrons accelerate due to centripetal force, and the accelerating charges radiate electromagnetic waves, losing energy. So the radius of electron’s orbit would steadily decrease. This model would lead a rapid collapse of the atom as the electron plunged into the nucleus.

The Bohr Model of the hydrogen atom
Niels Bohr attempted to explain the problems in Rutherford’s model. He developed a model with these assumptions: All forms of energy are ______________________. The electron in hydrogen atom can _________________ only certain specific orbits and no other. Electrons can ____________ from one orbit to another by emitting or absorbing a quantum of energy in the form of photon. Each allowed orbit in the atom corresponds to a specific _________________________. The orbit _____________ the nucleus represents the smallest amount of energy that the electron can have. The electron can remain in this orbit with out _____________________ energy even though it is being accelerated. When electron is in any particular orbit, it is said to be in a ________________________. Each stationary state represents an ________________________. The successive energy levels of an atom are assigned integral numbers, denoted by n=1, 2, 3… When the electron is in the lowest level (____________), it is said to be in the ____________________________. For a hydrogen atom, an electron in any level above the ground state is said to be in an ___________________. The picture shows an electron jumping from orbit n=3 to orbit n=2, emitting a photon of red light with an energy of 1.89 eV. Energy levels _______________________: any process that raises the energy level of electrons in an atom. Excitation can be the result of _________________________ the energy of colliding particles of matter, such as electrons, or photons of electromagnetic radiation. A photon’s energy is absorbed by an electron in an atom only if the photon’s energy corresponds _____________ to an energy-level difference possible for the electron. Excitation energies are ___________________ for different atoms. Atoms rapidly ________ the energy of their various excited states as their electrons return to the ground state. This lost energy is in the form of photons of specific ______________________, which appear as the spectrum lines in the characteristic spectrum of each _________________. A _________________________________ is a particular frequency of absorbed or emitted energy characteristic of an atom. The Bohr Model of the hydrogen atom Danish physicist Niels Bohr attempted to explain the problems in Rutherford’s model. He proposed in 1913 that electrons move around the nucleus of an atom in specific paths, on different levels of energy. All forms of energy are quantized. The electron in an atom can occupy only certain specific orbits and no other. Electrons can jump from one orbit to another by emitting or absorbing a quantum of energy in the form of photon. Each allowed orbit in the atom corresponds to a specific energy level. The orbit nearest the nucleus represents the smallest amount of energy that the electron can have. The electron can remain in this orbit with out losing energy even though it is being accelerated.

Ionization potential An atom can absorb sufficient energy to raise an electron to an energy level such that the electron is removed from the atom’s bound and an _________ is formed. The energy required to remove an electron from an atom to form an ion is called the atom’s ____________ _________________________. An atom in an excited state requires a ________________________ amount of energy to become an ion that does an atom in the ground state. Energy level diagram The energy level of an electron that has been completely removed form the atom (n = ∞) is defined to be 0.00 eV, all other energy levels have negative value The electron in the ground state has the lowest energy, with largest ________________________ value. _____________________________________ contains energy level diagrams for hydrogen and mercury Limitations of Bohr’s model It can not predict or explain the electron orbits of elements having ____________________ electrons When electron is in any particular orbit, it is said to be in a stationary state. Each stationary state represents an energy level. The successive energy levels of an atom are assigned integral numbers, denoted by n=1, 2, 3… When the electron is in the lowest level (n=1), it is said to be in the ground state. For a hydrogen atom, an electron in any level above the ground state is said to be in an excited state.

When electron goes up from lower to higher level, the atom absorbs a quantum of energy in the form of a photon. When electron goes down from higher to lower level, the atom emits a quantum of energy in the form of a photon.

If the energy of the photon of light is just right, it will cause the electron to jump to a higher level. When the electron jumps back down, a photon is emitted for each jump down. A photon without the right amount of energy (the pink one) passes through the atom with no effect. Photons with too much energy will cause the electron to be ejected which ionizes the atom

Energy levels excitation: any process that raises the energy level of electrons in an atom. Excitation can be the result of absorbing the energy of colliding particles of matter, such as electrons, or of photons of electromagnetic radiation. A photon’s energy is absorbed by an electron in an atom only if the photon’s energy corresponds exactly to an energy-level difference possible for the electron. Excitation energies are different for different atoms.

Ionization potential An atom can absorb sufficient energy to raise an electron to an energy level such that the electron is removed from the atom’s bound and an ion is formed. The energy required to remove an electron from an atom to form an ion is called the atom’s ionization potential. An atom in an excited state requires a smaller amount of energy to become an ion than does an atom in the ground state.

Energy level diagram ionization
The energy level of an electron that has been completely removed from the atom is defined to be 0.00 eV. All other energy levels have negative values. The electron in the ground state has the lowest energy, with largest negative value. Ground state

Ephoton = Einitial - Efinal
This formula can be used to determine the energy of the photon emitted (+) or absorbed(-). Ephoton = hf where h = 6.63 x Js This formula can be used to determine the energy of a photon if you know the frequency of it. Planck's constant, h, can be used in terms of Joule(s) or eV(s). (note: the Regents reference table only gives it in terms of Js)

Energy level is explained by Louis de Broglie’s particle-wave theory
..\..\RealPlayer Downloads\Matter Wave - De Broglie Wavelength.flv According to de Broglie, particles have wave nature: λ = h / p If we begin to think of electrons as waves, we'll have to change our whole concept of what an "orbit" is. Instead of having a little particle whizzing around the nucleus in a circular path, we'd have a wave sort of strung out around the whole circle. Now, the only way such a wave could exist is if a whole number of its wavelengths fit exactly around the circle. If the circumference is exactly as long as two wavelengths, say, or three or four or five, that's great, but two and a half won't cut it.

..\..\RealPlayer Downloads\Quantum Mechanics- The Structure Of Atoms.flv

Limitations of Bohr’s model
It can not predict or explain the electron orbits of elements having many electrons ..\..\RealPlayer Downloads\Quantum Mechanics.flv

The cloud model (Schrödinger model)
In this model, electrons are not confined to specific orbits, instead, they are spread out in space in a form called an electron ___________________. The electron cloud is densest in regions where the probability of finding the electron is ______________________. The cloud model represents a sort of history of where the electron has probably been and where it is likely to be _______________________. Atomic spectra When electrons jump from the lower to the higher number orbits, they __________________ a particular amount of energy and we can observe the _________________________ spectrum. When they fall back again they ______________________ the same amount of energy and we can observe the __________________ spectrum. The amount of energy absorbed or released in this way can be directly related to the wavelength at which we see the absorption and emission lines on the spectrum. When the electrons in excited atoms of an element in the gaseous state return to lower energy state, they produce at specific series of frequencies of electromagnetic radiation called the ___________________________ of the element. Each element has a characteristic ______________ that differs from that of every other element. The spectrum can be used to _____________________ the element, even when the element is mixed with other elements. The cloud model (Schrödinger model) In this model, electrons are not confined to specific orbits, instead, they are spread out in space in a form called an electron cloud. The electron cloud is densest in regions where the probability of finding the electron is highest. The cloud model represents a sort of history of where the electron has probably been and where it is likely to be going.

example The diagram represents alpha particle A approaching a gold nucleus. D is the distance between the path of the alpha particle and the path for a head-on collision. If D is decreased, the angle of deflection θ of the alpha particle would decrease increase remain the same

example Which diagram shows a possible path of an alpha particle as it passes very near the nucleus of a gold atom? 1 2 3 4

example In Rutherford's model of the atom, the positive charge
is distributed throughout the atom's volume revolves about the nucleus in specific orbits is concentrated at the center of the atom occupies most of the space of the atom

Class work Worksheet 6.1.1 #1, 3, 5-9, 11 Review questions #1-11

5/6 do now When a ray of light traveling in water reaches a boundary with air, part of the light ray is reflected and part is refracted. Which ray diagram best represents the paths of the reflected and refracted light rays? A B C D

Atomic spectra Explain atomic spectra using Bohr’s model of the atom.
Recognize that each element has a unique emission and absorption spectrum.

Atomic spectra According to Bohr’s model, electrons in atoms can be found in only certain discrete energy states.

Atomic spectra When electrons jump from the lower to the higher number orbits, they absorb a particular amount of energy and we can observe the absorption spectrum. When they fall back again they release the same amount of energy and we can observe the emission (bright-line) spectrum. The amount of energy absorbed or released in this way can be directly related to the wavelength at which we see the absorption and emission lines on the spectrum.

Each element has a characteristic spectrum that differs from that of every other element.
The emission spectrum can be used to identify the element, even when the element is mixed with other elements. Hydrogen spectrum Helium spectrum

Emission (bright-line, atomic) spectra
In a hot gas, when an electron in an atom in an excited state falls to a lower energy level, the energy of the emitted photon is equal to the difference between the energies of the initial and final states. Ephoton = Ei – Ef = hf Ei is the initial energy of the electron in its excited state and Ef is the final energy of the electron in the lower energy level.

Each energy difference between two energy levels corresponds to a photon having a specific frequency. For example: An electron in a hydrogen atom drops from the n = 3 energy level to the n = 2 energy level. The energy of the emitted photon is Ephoton = E3 – E2 = (-1.51 eV) – (-3.40 eV) = 1.89 eV Ephoton = 1.89 eV x 1.60 x J/eV = 3.02 x J Using Ephoton = hf, we can find the frequency of the emitted photon: f = 3.02 x J / (6.63x10-34 J∙s) = 4.56 x 1014 Hz which corresponding to red light

A specific series of frequencies, characteristic of the element, is produced when the electrons of its atoms in excited states fall back to lower states or to the ground state. When these emitted frequencies appear as a series of bright lines against a dark background, they are called a bright-line spectrum or an emission spectrum.

Absorption spectra In a cold gas, an atom can absorb only photons having energies equal to specific differences in its energy levels. The frequencies and wavelengths of these absorbed photons are exactly the same as those of the photons emitted when electrons lose energy and fall between the same energy levels.

Example An electron in a hydrogen atom drops from the n = 4 energy level to the n = 2 energy level. The energy of the emitted photon is Ephoton =Ei – Ef Ephoton =(-0.85eV)–(-3.40eV) Ephoton =2.55 eV Ephoton =4.08 x J

example Excited hydrogen atoms are all in the n = 3 state. How many different photon energies could possibly be emitted as these atoms return to the ground state? 1 2 3 4

3. The Nucleus Objectives
Know: Energy/mass relationship equation. Understand The connection between energy and mass and the fact that energy and mass can be converted into one another. Be able to Determine the energy contained in a given amount of mass. Convert universal mass units into MeV. Use/interpret a graph of energy vs. mass.

Nuclear mass and energy
According to Einstein’s mass-energy equation, any change in energy results in an equivalent change in _________. Mass-energy is conserved at all levels from cosmic to subatomic. In chemical reactions, if energy is ______________________, then the total mass must be decreased. If energy is ___________________________, then the total mass must be increased. However, the change of mass is too small to be measured. In nuclear reaction, the changes in energy relative to the masses involved are much large, the corresponding change in mass can be _______________________________________. Example: the total mass of two protons and two neutrons is 2( u u) = _______________ u The mass of a helium-4, is _____________ u The mass of the nucleus is _______________ than its components. This is true for every nucleus, with the exception for hydrogen-1, which has only one nucleon. When nucleons come together (_________________) to form a nucleus, energy is released and an equivalent amount of matter is lost. To break up nucleus (___________________), energy is absorbed, therefore mass is increased. Example: The energy emitted by the Sun originates from the process of fission fusion alpha decay beta decay Studying atomic nuclei The structure of the atomic nucleus and the nature of matter have been investigated using ___________________ _________________________. Particle accelerators use electric and magnetic fields to increase the kinetic energies of _____________________ _____________________, such as electrons and protons, and project them at speeds near the speed of light. Collisions between the high speed particles and atomic nuclei may disrupt the nuclei and release _____________ _______________. reactions between a 5 GeV hydrogen ion and a gold nucleus The Nuclear Force The nucleus is the core of an atom made up of one or more protons (except for one of the isotopes of hydrogen) and one or more neutron. The positively charged protons in any nucleus containing more than one proton are separated by a distance of m. In the nucleus, there are two major forces: A large repulsive electric (Coulomb) force between protons A very strong attractive nuclear force to keep the protons together. It is this nuclear force inside a nucleus that overcomes the repulsive electric force between protons and hold the nucleus together.

Nuclear force has rather unusual properties.
It is charge independent. This means that in all pairs neutron & neutron, proton & proton, and neutron & proton, nuclear forces are the same. at distances cm, the nuclear force is attractive and very strong, 100 times stronger than the electromagnetic repulsion. Strongest forces known to exist, nuclear force is also called strong force. the nuclear force very short range force. At distances greater than a few nucleon diameters, the nuclear attraction practically disappears. As the nucleus gets bigger, the attractive nuclear force between the nucleons gets smaller, the nucleus becomes very unstable and starts to break apart, causing radioactive decay.

Universal mass unit The universal mass unit, or atomic mass unit, is defined as 1/12 the mass of an atom of carbon-12, which is a carbon atom having 6 protons, 6 neutrons, and 6 electrons. In universal mass unit, the mass of the proton is u, the mass of the neutron is u, the mass of an electron is u. In SI units, a mass of one universal mass unit, 1 u = 1.66 x kg.

Mass-energy relationship
Einstein showed that mass and energy are different forms of the same thing and are equivalent. E = mc2 E is energy in joules, m is mass in kg, c is the speed of light in vacuum 3.00x108 m/s

Nuclear mass and energy
According to Einstein’s mass-energy equation, any change in energy results in an equivalent change in mass. Mass-energy is conserved at all levels from cosmic to subatomic. In chemical reactions, if energy is released, then the total mass must be decreased. If energy is absorbed, then the total mass must be increased. However, the change of mass is too small to be measured.

In nuclear reaction, the changes in energy relative to the masses involved are much larger, the corresponding change in mass can be measured. Example: total mass of two protons and two neutrons is 2( u u) = u The mass of a helium-4 is u The mass of the nucleus is less than its components. This is true for every nucleus, with the exception for hydrogen-1, which has only one nucleon.

Nuclear fission and fusion
Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei). Fission of heavy elements is an exothermic reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments (heating the bulk material where fission takes place). Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy. The fusion of two nuclei with lower masses than iron (which, along with nickel, has the largest binding energy per nucleon) generally releases energy while the fusion of nuclei heavier than iron absorbs energy

Studying atomic nuclei
The structure of the atomic nucleus and the nature of matter have been investigated using particle accelerators. Particle accelerators use electric and magnetic fields to increase the kinetic energies of charged particles, such as electrons and protons, and project them at speeds near the speed of light. Collisions between the high speed particles and atomic nuclei may disrupt the nuclei and release new particles. Review – dual nature of light, quantum theory

example Universal mass unit (u) is used: 1 u = 9.31 x 102 MeV
What is the amount of energy in one kilogram of mass? E = mc2 E = (1 kg) x (3.00 x 108 m/s)2 = 9.00 x 1016 J Kilogram is very big unit of mass in the reference of mass-energy conversion. Universal mass unit (u) is used: 1 u = 9.31 x 102 MeV

example According to the chart, the energy equivalent of the rest mass of a proton is approximately 9.4 x 102 MeV 1.9 x 103 MeV 9.0 x 1016 MeV 6.4 x 1018 MeV When the unit is u (atomic mass unit), converts the mass into MeV instead of Joules. 1 u = 9.31 x 102 MeV u = 9.4 x 102 MeV

Example The graph represents the relationship between mass and its energy equivalent. The slope of the graph represents the electrostatic constant gravitational field strength the speed of light squared Planck's constant E = mc2

4. The standard model of particle physics - objectives
Standard model of particle physics – notes Objectives State the __________________________________ of particle physics Describe the _________________________________ in nature Classify ______________________________________. Particle physics __________________________________ is a branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them. It is also called “_________________________________________", because many elementary particles do not occur under normal circumstances in nature, but can be created and detected during energetic collisions of other particles, as is done in particle accelerators Standard model of particle physics The Standard Model is the name given to the current theory of fundamental particles and how they interact Standard model of physics is a _______________________, used to explain the existence of all the particles (_____ fundamental particles) that have been observed and the _______________ ( ___ fundamental forces in nature) that hold atoms together or lead to their decay. Forces In _________________________: Force is regarded as a vector causing an object to accelerate In ___________________________________: since forces are brought about as a result of an exchange of particles, therefore particles are referred as _____________________________________________. The fundamental forces in nature There are __________________ fundamental forces in nature: strong (nuclear), Electromagnetic, Weak, Gravitational. The _____________________ force is another short-range nuclear force that is responsible for the decay of some nuclear particles. 4. The standard model of particle physics - objectives State the standard model of particle physics Describe the fundamental forces in nature Classify subatomic particles

Standard model of particle physics
Force carriers The force carriers of the Standard Model are bosons, known as gauge bosons: ______________ mediating the strong interactions ______________ mediating the electromagnetic interactions _______________________ mediating the weak interactions The name for the carrier particle of gravitational interactions is the _____________________ Sub-atomic particles Although the Proton, Neutron and Electron have been considered the fundamental particles of an atom, recent discoveries from experiments in atomic accelerators have shown that there are actually ______ fundamental particles. They are divided into two classes, consisting of _______________ and _________________. The proton and neutron are no longer considered fundamental particles in this sub-atomic classification. What are leptons? A ______________ has a ____________________________ that of a proton, the _______________ classification of sub-atomic particles consists of 6 ___________________________________________: Electron Muon Tau Electron Neutrino Muon Neutrino Tau Neutrino The _________________________________________________ give the names, symbols and charges of the six members of the lepton family. Standard model of particle physics ..\..\RealPlayer Downloads\CERN- The Standard Model Of Particle Physics.flv The Standard Model of particle physics (formulated in the 1970s) describes the universe in terms of Matter (fermions - 24) and Force (bosons - 4). Unlike the force-carrying particles, the matter particles have associated antimatter particles, such as the antielectron (also called positron) and antiquarks. So there are together 24 fermions. force Relative strength Range of force Force carrier mass charge Strong (nuclear) 1 ~ 10-15m gluon electromagnetic 10-2 ~ 1/r2 photon weak 10-13 < 10-18m W boson Z boson 80.6 GeV 80.6 GeV 91.2 GeV +e -e gravitational 10-38 graviton force Relative strength Range of force Force carrier mass charge Strong (nuclear) 1 ~ 10-15m gluon electromagnetic 10-2 ~ 1/r2 photon weak 10-13 < 10-18m W boson Z boson 80.6 GeV 80.6 GeV 91.2 GeV +e -e gravitational 10-38 graviton

The fundamental forces in nature
Classification of subatomic particles Particles can be classified according to the types of __________________________ they have with other particles. A particle that interacts through the strong nuclear force, as well as the electromagnetic, weak and gravitational forces is called a _________________________________. A particle that interacts through the electromagnetic, weak and gravitational forces, but not the strong nuclear force, is called a _____________________. A __________________________ group can be subdivided into _________________ and __________________. Baryons are made of _____________________, the charges on a baryon can be ____________________. examples of baryons are _____________________________________________________. The term "baryon" is derived from the Greek βαρύς (barys), meaning “____________________.“ Mesons are made a ___________________________________________ pair, the charge on a mesons is 0. mesons is a particle of ______________________________________ mass. All ___________________ are constructed of ____________________. A ___________________ is made up of 3 quarks, for example: A __________________ consists of up, up, down quarks (uud) A _________________ consists of up, down, down quarks (udd) When quarks combine to form baryons, their _________________add algebraically to a total of _______________. The fundamental forces in nature There are four known forces. Two of these forces are only seen in atomic nuclei or other subatomic particles. Aside from gravity, all the macroscopically observable forces — such as friction & pressure as well as electrical & magnetic interaction — are due to electromagnetic force. Gravitational (not in standard model) Electromagnetic strong nuclear Weak nuclear ..\..\RealPlayer Downloads\The Weak and Strong Nuclear Forces (9 of 15).flv The weak nuclear force is another very short-range nuclear force that causes transformation of protons to neutrons and vice-versa, along with other radioactive (gives off photons and other particles) phenomena.

force Strong nuclear Electro- Magnetic Weak nuclear gravitational
The Standard Model describe the force between two particles in terms of the exchange of virtual force carrier particles between them. force Relative strength range Force carrier mass charge Strong nuclear 1038 ~10-15 m gluon Electro- Magnetic 1036 ~1/r2 photon Weak nuclear 1025 10-18 m W boson Z boson 80.6 GeV 91.2 GeV +e -e gravitational 1 graviton

GRAVITY Gravitation is a force of attraction that acts between each and every particle in the Universe. It is the weakest of the four fundamental forces. It is always attractive, never repulsive. It pulls matter together, causes you to have a weight, apples to fall from trees, keeps the Moon in its orbit around the Earth, the planets confined in their orbits around the Sun, and binds together galaxies in clusters.

THE ELECTROMAGNETIC FORCE
The electromagnetic force determines the ways in which electrically charged particles interact with each other and also with magnetic fields. This force can be attractive or repulsive. This force holds the atoms together. This force also governs the emission and absorption of light and other forms of electromagnetic radiation.

THE STRONG NUCLEAR FORCE
The strong nuclear force binds together the protons and neutrons that comprise an atomic nucleus and prevents the mutual repulsion between positively charged protons from causing them to fly apart. The strong nuclear force interaction is the underlying source of the vast quantities of energy that are liberated by the nuclear reactions that power the stars.

THE WEAK NUCLEAR FORCE The weak nuclear force causes the radioactive decay of certain particular atomic nuclei. In particular, this force governs the process called beta decay whereby a neutron breaks up spontaneously into a proton, and electron and an antineutrino.

LONG-RANGE and SHORT-RANGE FORCES
The strong and weak nuclear interactions are effective only over extremely short distances. The range of strong force is about meters and that of the weak force is meters. In contrast, the electromagnetic and gravitational interactions are long-range forces, their strengths being inversely proportional to the square of distance.

Force carriers According to modern quantum theories, the various fundamental forces are conveyed between real particles by means of virtual particles. The force-carrying particles (which are known as gauge bosons) for each of the forces are as follows: electromagnetic force - photons; weak nuclear interaction - very massive 'W' and 'Z' bosons; strong nuclear interaction - gluons. gravitation - graviton.

The fundamental forces
Relative strength Range of force Force carrier mass charge Strong (nuclear) 1 ~ 10-15m gluon electromagnetic 10-2 ~ 1/r2 photon weak 10-13 < 10-18m W boson Z boson 80.6 GeV 80.6 GeV 91.2 GeV +e -e gravitational 10-38 graviton

example Which force is responsible for a neutron decaying into a proton? Which force bonds quarks together into particles like protons and neutrons? Which force governs the motion of an apple falling from a tree? Weak force strong force Gravitational force

What are you made of? What forces hold you together?

Sub-Atomic Particles Although the Proton, Neutron and Electron have been considered the fundamental particles of an atom, recent discoveries from experiments in atomic accelerators have shown that there are actually 12 fundamental particles (with 12 antiparticles). Protons and neutrons are no longer considered fundamental particles in this sub-atomic classification. ..\..\RealPlayer Downloads\CERN- The Standard Model Of Particle Physics.flv

The fundamental particles are classified into two classes: quarks and leptons

Hadrons and lepton Particles can be classified according to the types of interactions they have with other particles. A particle that interacts through the strong nuclear force, as well as the electromagnetic, weak and gravitational forces is called a hadron. A particle that interacts through the electromagnetic, weak and gravitational forces, but not the strong nuclear force, is called a lepton.

Hadrons – baryons & mesons
Hadrons group can be subdivided into baryons and mesons. Baryons are made of three quarks, the charges on a baryon can be 0, +1, or -1 examples of baryons are neutrons, protons. The term "baryon" is derived from the Greek βαρύς (barys), meaning "heavy.“ Mesons are made a quark-antiquark pair, mesons is a particle of intermediate mass.

All hadrons are constructed of quarks.
A baryon is made up of 3 quarks, for example: A proton consists of up, up, down quarks A neutron consists of up, down, down quarks When quarks combine to form baryons, their charges add algebraically to a total of 0, +1, -1.

example Baryons may have charges of +1e and + 4/3 e +2e and +3e

example Protons and neutrons are examples of positrons baryons mesons
quarks

What are Leptons? A lepton has a mass much less than that of a proton, the lepton classification of sub-atomic particles consists of 6 fundamental particles: Electron Muon Tau Electron Neutrino Muon Neutrino Tau Neutrino The reference tables give the names, symbols and charges of the six members of the lepton family.

Electron, Muon and Tau Leptons
The Electron remains a fundamental particle, as if was in the Atomic Theory. It has an electrical charge of (-1) and plays an active role in chemical reactions. The Muon is primarily a result of a high-energy collision in an atomic accelerator. The Muon is similar to an Electron, only heavier. The Tau particle is similar to a Muon, only heavier yet. Muon and Tau particles are unstable and exist in nature for a very short time.

Neutrinos Neutrinos are small and have no electrical charge. This makes them extremely difficult to detect. They can possess a large amount of energy and the very rare times they do collide with another particle, that energy can be released. There are 3 types of neutrinos: Electron Neutrino, which has no charge and is extremely difficult to detect Muon Neutrino, which is created when some atomic particles decay Tau Neutrino, which is heavier than the Muon Neutrino.

Quarks Another group of sub-atomic particles are the Quarks. Just like their name, they exhibit unusual characteristics. There are 6 fundamental particles among the Quarks are: Up and Down Quarks Charm, Strange, Top and Bottom Quarks Other particles are made up of combination of Quarks. The reference table gives the names, symbols, and charges of the six quarks.

Up and Down Quarks The Up Quark has an electrical charge of (+2/3). The Down Quark has an electrical charge of (-1/3). The Proton is made up of two Up Quarks and one Down Quark. The electrical charge of the proton is then: (+2/3) + (+2/3) + (-1/3) = (+1). The Neutron is made up of one Up Quark and two Down Quarks. The resulting electrical charge of the Neutron is: (+2/3) + (-1/3) + (-1/3) = (0).

Charm, Strange, Top and Bottom Quarks
The Charm Quark has the same electrical charge as the Up Quark but is heavier. The Top Quark is then heavier than the Charm. The Strange Quark has the same electrical charge as the Down Quark but is heavier. The Bottom Quark is heavier than the Strange.

baryons mesons 6 types 3 quarks quark and antiquark 6 types of quarks

antiparticle An antiparticle is associated with each particle.
An antiparticle is a particle having mass, lifetime, and spin identical to the associated particle, but with charge of opposite sign (if charged) and magnetic moment reversed in sign. An antiparticle is denoted by a bar over the symbol of the particle. Example: p, stands for antiproton, which can be described as a stable baryon carrying a unit negative charge, but having the same mass as a proton.

A positron (+e) is a particle whose mass is equal to the mass of the electron and whose positive electric charge is equal in magnitude to the negative charge of the electron. Positron is the antiparticle of electron (e). The antineutron (n) has the same mass as the neutron and is also electrically neutral. However the magnetic moment and spin of the antineutron are in the same direction, whereas, the magnetic moment and spin of the neutron are in opposite directions. Antiparticle for a neutrino is identical to the neutrino except for their direction of spin.

There are total of 24 basic particles
quarks antiquarks leptons antileptons 6 6 6 6 There are total of 24 basic particles

antimatter Antimatter is material consisting of atoms that are composed of antiprotons, antineutrons, and positrons.

Examples The subatomic particles that make up both protons and neutrons are known as electrons nuclides positrons Quarks A lithium atom consists of 3 protons, 4 neutrons, and 3 electrons. This atom contains a total of 9 quarks and 7 leptons 12 quarks and 6 leptons 14 quarks and 3 leptons 21 quarks and 3 leptons

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