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