September 06, 2011

Relativity and similtineaitydigital media downloads

Time dilation

Michelson - Morley Interferometer

Michelson - Morley Experiment

Length Contraction

another external michelson-morley

Light Clock - Time dilationexternal link

Twin paradox illustrationdigital media downloads

The Electron Volt?

units?

Derivation?

The electron volt is the same as what unit ? explain

eΔV =

Pair Production and Annihilation

A B Which is which?

Explain the process for each?

What must be conserved in each?

Explain the equation for pair prod.

hfmin = 2mec2

Why me and not mp ?

why 2?

what does hfmin represent

Blackbody radiation

What does blackbody radiation mean?

What happens when objects increase in temperature?

If we measured the radiation emitted as temperature increased, what would it read?

classical theory (wave) vs quantum (particle)

Phet

Ultraviolet catastrophe - theory and experiment contradict each other. The contradiction happens in the ultraviolet region (wavelength)

Classical suggest as wavelength approaches zero energy should be infinite.

Experiment shows as wavelength approaches zero energy approaches zero as well.

Planck's hypothesis and constant

What does Planck suggest?

instead of resonantors being able to emit energy at any speed or energy?

September 06, 2011

Planck's hypothesis and constant

Planck proposed submicroscopic charged oscillators that could only have discreet quantities of energy(quantized). ** not a broad range or spectrum of energies.

The light emitted could be thought of individual packets of energy. "Particles" of light, each with a set amount of energy.

E = nhf

n is an integer

h is Planck's constant = 6.63x10-34 Joule*seconds

f is the frequency

Photoelectric effect review

What is the photoelectric effect? explain

Phet Simulation - discussphet link

photoelectric effect videoWhat is happening?

Problem

If electrons cease being emitted from a metal when 500 nm light is incident upon the surface, then what is the minimum energy required to cause the photoelectric effect? in eV and Joules (Hint: Cutoff wavelength)

How much kinetic energy will the electrons have? (if they have not been emitted from the surface?)

The work funtion? in eV and in Joules

What is the KEmax of a photoelectron, produced by a 400 nm light shining on the same material as above? in eV and Joules

What is the maximum speed of an electron with this kinetic energy? [ KE=1/2mev2 **this formula requires Joules]

What voltage would be required to stop the electrons produced by the 400 nm light source?

Try #13,14 and 11 and 12 in chapter 27

in order of increasing difficulty

KE formula from academic

mass of electron on the equation sheet in the constants

September 06, 2011

Diffraction of x-raysCompton Effect or Compton Scattering

The shift in wavelength of the x-ray is due the the fact that the electron that was at rest is now __________? explain

Discuss the energy change for the electron? for the light particle (photon)

Wavelength of the photon?

Why it must be an x-ray?

**not done mathematically

Producing an x-ray

eΔV = hfmax = (hc)/λmax

What is happening in the picture?

What happens to the energy of the electron?

What is created? Where does it get it's energy from? does this contradict conservation of energy?

Explain the equation

Debroglie waves

Dual nature?

What does the nature of light depend upon? explain

Debroglie equation : p = h/λ (derivation on page 887)

**electromagnetic waves have momentum even though they have no mass.

Atomic SpectraRutherford scattering

Models of the atom? (Phet Sim.)

NewtonJJ TomsonRutherfordBohr DeBroglieSchrodinger

September 06, 2011

absorption and emission

Laser - Light Amplification by Stimulation of Radiation

phet laser

September 06, 2011

try 11 - 14 chapter 28

Hydrogen atom

E n = -13.6 / n2 eV

Discuss Bohr model for hydrogen on page 908

what we know about nuclear - supercouse (pitt) excellent

Half Life - Conceptual

Time it takes until half the substance is left. Conceptual

Ex. If half life is 10 years, how much of a substance is left after 30 years?

3 half lives

If it is not an equal amount of half livest = timet1/2 = half life

N = amount of substance leftN0 = amount of substance

equations 29.4b and 29.4c

Nuclear Physics

What holds a nucleus together?

What cause a nucleus to come apart? or decay?

Forces?

Why is nuclear energy important to us? examples

**As little as 4 kg of plutonium can be used as a nuclear weapon - baseball size : source federation of american scientists

Simple Binding Energy - copyright schaum's guide ver9, page 402

What is the binding energy of 12C?

One atom of 12C consists of 6 protons and 6 electrons, and 6 neutrons. The mass of the uncombined protons and electrons is the same as six 1H (if we ignore the very small binding energy of each proton-electron pair). The component particles may thus be considered six 1H atoms and six neutrons. A mass balance may be computed as follows.

six 1H atoms (protons)= 6 x 1.0078 u = 6.0468 uMass of six neutrons = 6 x 1.0087 u = 6.0522 uTotal mass of components = 12.0990 uMass of 12C atom = 12.0000 uLoss in mass on forming 12C = 0.0990 uBinding energy = 931 MeV/u *0.0990 u) = 92 MeV

The total energy of the bound system (stable nucleus) is less than the combined energy of the separated nucleons. This can be thought of the energy required to break it apart.

See Appendix B

September 06, 2011

Binding Energy

Example problem 29.2

Deuterium - splits - (1proton + 1 neutron)

How much energy must we add to split this atom apart?

**use page 967 (table 29.4 for mass of proton and neutron) use Appendix B for Deuterium atom mass

Before looking at the answer on page 943

The total energy of the bound system (stable nucleus) is less than the combined energy of the separated nucleons. This can be thought of the energy required to break it apart.

Z or atomic number is the number of protons

A or mass number is the number of nucleons (protons and neutrons)

* use page 967 Appendix B for needed values

968 - #10

Read through carefully, Example 30.2- page 975

page 944 - calculate Binding Energy of Helium -3

· 2 protons· 3 nucleons - therefor their must be 1 neutron· mass of helium -3 from Appendix B

Practice For practice * use page 967 or Appendix B for needed values

968 - chapeter 29.10

Deuterium (sometimes D)

Using the Concept of Binding Energy to "get" energy

Fission

Fusion

Radioactive Decay

The curve peaks at A = 60, which means that nuclei further away from 60 are held less tightly and allows for both fission and fusion reactions (page 944, good to read)

FissionPhet sim

**The total mass of the products is less than the original mass of the heavy nucleus. Note - a great deal of energy is needed to get this started.

Example 30.2- page 975

Calculate the total energy released if 1.00 kg of U(235) undergoes fission. Q=208 MeV/event.

How many kg of U(235) would be needed annually ; 4x1020 J

page 974

September 06, 2011

Fission

Example 30.2- page 975

Calculate the total energy released if 1.00 kg of U(235) undergoes fission. Q=208 MeV/event.

How many kg of U(235) would be needed annually ; 4x1020 J

How many kg of U(235) would be needed annually ; 4x1020 J

How many kg of U(235) would be needed annually ; 4x1020 J

Try problem 30.6 page 1004

What do we do with the 40% efficient?

Try this problem, after discussing watts and 40 percent efficient

Energy Total = # of Events * Energyper_event

P*t = Energy TotalEnergy Total = # of Events * Energyper_event P*t = Energy Total

September 06, 2011

6.75x1024 events/day * 1mol/6.02x1023 events* 235 g/mol * 1k/1000g = 2.63 kg /day

Each individual atom of a mol of material will have an event (fission) : therefore 6.02x1023 can be molecules, events, atoms

page 982 Example 30.3

Fusion

*When two light nuclei combine to form a heavier nucleus, but because the final nucleus is less than the masses of the original nuclei, there is loss of mass and release of energy. Note - a great deal of energy is needed to get this started.

H or DWhat happens when the sun runs out of fuel? What is the fuel? page 982 Example 30.3

*When two light nuclei combine to form a heavier nucleus, but because the final nucleus is less than the masses of the original nuclei, there is loss of mass and release of energy. Note - a great deal of energy is needed to get this started.

Fusion

Exercise 30.3 page 982

Find the Energy released in the fusion of two helium-2 nuclei

Extra practice 30.2 30.6, 30.10

Deuterium

page 982 Example 30.3

*When two light nuclei combine to form a heavier nucleus, but because the final nucleus is less than the masses of the original nuclei, there is loss of mass and release of energy. Note - a great deal of energy is needed to get this started.

Fusion

Exercise 30.3 page 982

Find the Energy released in the fusion of two helium-2 nuclei

Extra practice 30.2 30.6, 30.10

Deuterium

DecayDemomysterious decay with labpro, alpha, beta, gamma - verify with paper, lead

September 06, 2011

Alpha Decay

Example 29.5 page 950 (todo)

29.30 as an example - write the equation and calculate binding energy involved

Is this energy released or energy absorbed?

Alpha Decay

*In order for alpha emission to occur, the mass of the parent must be greater than the combined mass of the daughter and the alpha particle. (pg 969,Serway Faughn)

Use table on 967

Thorium is missing from Appendix B

29.30 Energy released and conservation of energy and momentum of Alpha Decay

· Find the Energy given off - assume the beta particle has no mass and neglect the neutrino·· Find the max speed of the beta particle - if it gets all the energy·· Find the momentum of the beta particle and the copper, assume the nickel particle had no momentum originally - I will discuss

29.30 as an example - write the equation and calculate extra energy (mass) involved

Is this energy released or energy absorbed? · in decay - an atom is split apart - fission - and releases energy· The daughters have less mass than the parent

Alpha Decay

find another alpha decay - todo

Beta DecayPhet sim

Example 29.6 page 950

*Appendix BBeta Decay

Example 29.6

Try Exercise 29.6 page 951

September 06, 2011

Page 969

Find energy release and complete the equation

186.2

186.2

186.2

Gamma DecayRadioactive Decay

September 06, 2011

Nuclear Chain Reactions