PHYSICS 107: FINAL EXAM
30 Cards in this Set
| Front | Back |
|---|---|
|
What is the approximate age of the bone
|
24,000 years
|
|
How much energy is released
|
28 MeV
|
|
Where does the energy of the Sun come from
|
Nuclear fusion
|
|
What is the biggest obstacle to building a nuclear bomb
|
Separating the uranium isotopes
|
|
What is the “easy” fusion reaction used on earth
|
Deuterium + tritium helium + neutron
|
|
What are the challenges for building a fusion reactor
|
The electric repulsion between protons, reaching a temperature of 100 million degrees Kelvin, prevent the hot plasma form destroying the reactor walls, passing the break even point (all of the above)
|
|
What are the advantages of a fusion reactor
|
A plentiful supply of fuel and no contribution to the greenhouse effect
|
|
Which part of a fission reactor is used to prevent it from a meltdown
|
The control rods- also reduce fission by absorbing neutrons
|
|
What are the advantages of a fission reactor
|
A long-term supply of fuel, no contribution to the greenhouse effect, no emission of mercury and other poisonous elements, the technology is available (all of the above)
|
|
What are the challenges of using solar cells for electricity production
|
They are too expensive, operation on a large scale has not been demonstrated, getting the generated electrons and holes to the contacts (all of the above)
|
|
What are the advantages of using solar cells for electricity production
|
A plentiful supply of solar energy, no contribution to the greenhouse effect, the technology is available, they do not pollute the air or create radioactive waste (all of the above)
|
|
What does the number 235 in 235 U stand for
|
The number of nucleons
|
|
What is the area of solar cells needed to satisfy the electricity needs of the US
|
100 x 100 km 2
|
|
Which of the following theories aims at unifying the different forces
|
Quantum theory
|
|
What is spin in particle theory
|
An internal rotation of a particle
|
|
What is the spin of the electron
|
½
|
|
What is the spin of a photon
|
1
|
|
Which is the antiparticle of the electron
|
The positron
|
|
What is the antiparticle of the photon
|
The photon
|
|
Which of the following particles are fermions
|
Electron, quark, and neutrino
|
|
What does SU(2) stand for
|
The symmetry group of the weak interaction
|
|
What does SU(2) stand for? The symmetry group of the weak interaction
|
U(1) not symmetric (fermion= electron, boson= photon); SU(3) strong force (quarks: red, green blue)
# = fermions; # 2 – 1 = bosons to mediate force
|
|
What is the quantum number that is conserved due to SU(3) symmetry
|
Color
|
|
What does the Pauli principle say
|
Two electrons and fermions cannot be at the same place at the same time
|
|
Which of the following isotopes can be used for a nuclear bomb
|
239Plutonium and 235Uranium
|
|
What would happen to the energy production of the Sun if the electromagnetic coupling constant a increased by a factor of two
|
Much less, because the electric repulsion between protons is bottleneck
|
|
What occurs in a solar cell
|
A photon produces an electron hole pair
|
|
Which of the following field equations correspond to the photon
|
The Maxwell equations
|
|
Which of these particles obey Pauli’s exclusion principle
|
Electrons- yes; photon- no
|
|
The standard model describes which of the following forces
|
Weak, strong, and electromagnetic
|
PHYSICS 107: FINAL EXAM