Practice Test 3
Phys 1404­001
Short Questions:
1. What were the two main postulates that are the foundations for the special theory of relativity?
2 . What are the numerical limits for the gamma factor that is so important in relativity?
3. The atomic bomb dropped on Nagasaki at the end of World War II had the energy equivalent of 9
about 21,000 tons of TNT (1 ton TNT = 4.3x10 J). How much mass was converted to energy in this explosion?
4. How fast must an object be moving for its length to appear only half of its length when at rest?
5. What is the photo­electric effect ? and Does it support the wave or particle picture of light? Briefly explain how.
6. The electron in the ground state of a hydrogen atom has a binding energy of 13.6 eV, by how much is the n = 4 electron state in H bound in the simple model?
7. Briefly explain the Bohr model of the H atom. What fundamental quantity was quantized in this model?
8. What experimental puzzle led Max Planck to come up with his famous constant? What was the specific proposal that allowed him to solve this problem?
9. What is the fundamental process related to beta decay of an unstable nucleus? 10. If a specific nuclear isotope has a half­life of 26.8 days, how long will it take for a sample of this substance to decay to one sixteenth of its original amount ?
11. List two different versions of what is known as the Heisenberg Uncertainty Principle and briefly explain what each expression means.
13. What specific particles make up Alphas, Beta, and Gamma radiation ?
Multi­part, Show your work type Problems:
I. A proton and an anti­proton, each moving at 99% of the speed of light collide head­on at a high­
­27 energy accelerator. Take mo = 1.67x10 kg
A) What is the total relativistic energy of each of these particles ?
B) How large is each particles momentum ?
C) How much energy is released when these particles annihilate each other ? II. Consider the 3p electronic ‘sub­shell’ in a simple atom.
A) Specify the primary and orbital quantum numbers ( n and l ) for this sub­shell.
B) How many electrons can occupy this shell ? Explain.
C) What are the other quantum numbers for each allowed 3p electron state.
Briefly explain what these other quantum numbers represent.
D) Sketch the electronic energy levels for a hydrogen atom (very roughly to scale) from the ground state up to at least two levels above this 3p sub­shell and label
each of these levels by their sub­shell or n, l designation.