Announcements Grade Breakpoint Adjustment Grade Breakpoint Adjustment Exam 4 Exam 4 Final Exam Final...
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Transcript of Announcements Grade Breakpoint Adjustment Grade Breakpoint Adjustment Exam 4 Exam 4 Final Exam Final...
Announcements Grade Breakpoint Adjustment Exam 4 Final Exam
– Multiple choice (16 questions)– Problems like problems on midterms– Problems from midterms with different
numbers
Fusion--Two nuclei combine to form a heavier nucleus
First reaction in early stars
11H
+ 11H → 2
1H + e+ + νe
mass before - mass after = energy released/c 2
(2MH1 – 2Me) – (MH2 –Me + Me) =
(2x1.0078250u - 0.0005486u) - 2.0141018 u
= 0.0009996 u (1uc2=931 MeV)
Q = 0.93 MeV
Fusion--Two nuclei combine to form a heavier nucleus
More reactions in stars
11H
+ 11H → 2
1H + e+ + νe
11H
+ 21H → 3
2He
11H
+ 32He → 4
2He + e+ + νe
32He + 3
2He → 42He + 1
1H + 11H
Fusion--Two nuclei combine to form a heavier nucleus
One reaction in a hydrogen bomb
21H
+ 31H → 4
2He + n
Total mass before -Total mass after = energy released
5.0302 u - 5.0113 u = .0189 u ≈ 17.6 MeV
Fusion Reactors Much less radioactivity
– Mostly produces helium-4, but materials near the reaction can absorb neutrons, etc.
Hydrogen is everywhere! It doesn’t work . . . Yet
– Protons repel each other until you get them really close
– Really high temperatures needed
Plasma Fusion
TFTR
Inertial Confinement Fusion
Other practical uses of nuclear physics…
Nuclear medicine– Nuclear treatment (destroy tumors)– Tracer imaging– PET scan– NMR (MRI) ?
Power for space probes Dating materials Sterilization of equipment or food Smoke detectors
Irradiated with
neutrons
Detected electrons emitted
Van Dyck’s
“Saint Rosalie Interceding for the
Plague-Stricken of Palermo”
After a few hours- manganese
(found in umber,A dark pigment)
After 4 days- phosphorous
(found in charcoal)
Jackson Pollock – Galaxy
Irradiated with neutrons
Jackson Pollock – Galaxy
Detected secondaryemission of truth
And beyond Particle physics, QCD, the standard
model Unification theories / theory of
everything String theory
3 Nephi 12:3Yea, blessed are the poor in spirit who come unto me, for theirs is the kingdom of heaven.
Brothers and sisters, whatever your distress, please don’t give up and please don’t yield to fear. --- Elder Jeffrey R. Holland, General Conference, April 2006
Review Request deBroglie wavelength for relativistic
particle of given Ek
Review Request Velocity transform
Review Postulates of Relativity
Time dilation
Length contraction
Lorentz transformations – velocity transform
Relativistic momentum and energy
Review Photons
Bohr Atom
de Broglie Waves
Review Notation – atomic number, mass
number
Half Life
Review Nuclear Decay
– Gamma
– Beta –
– Beta +
– Ec
– Alpha
Review Fission
Fusion