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Get the formative assessment: FA27.2.docx
Get the Hadron Reference sheet: ReferenceForHadrons.pdf
Get more practice problems: Worksheet-ProblemsFrom27.2.docx
The formative assessment solved:
1. How fast must an alpha particle (m = 6.64x10−27 kg) go to get within 5.0x10-15 m of an Iron nucleus (Z = 26)
(2.69x107 m/s)
2. What is the wavelength of the photon associated with an electron transition from n = 2 to n = 7 in a hydrogen atom? Is the photon being absorbed, or emitted?
(397 nm, absorbed)
3.
What is the radius of U-235?
(7.41x10-15 m)
If the uncertainty of an electron's position is 1.20x10-10 m, what is the minimum uncertainty (the total range) of its velocity?
(4.82x105 m/s)
4. Fill in the table below the decay and the reaction. For the decays, find the missing particle. For the reactions, indicate if it is possible, or indicate every law it violates:
Watch the videos to grade your FA:
5.
Write the quark combinations that make up a proton and a neutron:
p = n =
uud, udd
Identify the following quark combinations as either a meson, or a baryon. Determine the baryon number, strangeness, and the charge of each:
Watch the video to grade your FA:
Problems from 27.2 - Atomic Physics
Closest Approach:
1. An alpha particle (m = 6.64x10−27 kg) going 5.14x106 m/s will get how close to a silver (Z = 47) nucleus if it hits head on? (2.47x10-13 m)
2. A speeding alpha particle (m = 6.64x10−27 kg) hits a mercury (Z = 80) nucleus head on. If it comes within 17.0 nm of the nucleus’ center, how fast was it going to start with? (2.56x104 m/s)
3. An alpha particle (m = 6.64x10−27 kg) going 4.12x106 m/s will get how close to a bismuth (Z = 83) nucleus if it hits head on? (6.80x10-13 m)
4. A speeding alpha particle (m = 6.64x10−27 kg) hits a lead (Z = 82) nucleus head on. If it comes within 12.0 nm of the nucleus’ center, how fast was it going to start with? (3.08x104 m/s)
5. An alpha particle (m = 6.64x10−27 kg) going 2.37x106 m/s will get how close to a gold (Z = 79) nucleus if it hits head on? (1.95x10-12 m)
Electron Transitions:
6. What is the wavelength of the photon associated with an electron transition from n = 3 to n = 1 in a hydrogen atom? Is the photon being absorbed, or emitted? (103 nm, emitted)
7. What is the wavelength of the photon associated with an electron transition from n = 3 to n = 6 in a hydrogen atom? Is the photon being absorbed, or emitted? (1095 nm, absorbed)
8. What is the wavelength of the photon associated with an electron transition from n = 2 to n = 1 in a hydrogen atom? Is the photon being absorbed, or emitted? (122 nm, emitted)
9. What is the wavelength of the photon associated with an electron transition from n = 2 to n = 4 in a hydrogen atom? Is the photon being absorbed, or emitted? (487 nm, absorbed)
10. What is the wavelength of the photon associated with an electron transition from n = 6 to n = 2 in a hydrogen atom? Is the photon being absorbed, or emitted? (411 nm, emitted)
Nuclear Radius or Heisenberg:
11. What is the radius of C-14 nucleus? (2.89x10-15 m)
12. What is the likely mass number of a nucleus with a radius of 3.51x10-15 m? (25)
13. To effect an alpha decay, an alpha particle must “borrow” 31.1 MeV of energy. What time does it have to escape? (1.06x10-23 s)
14. An Alpha particle takes 1.80x10-23 s to "tunnel" through a potential barrier. What is the amount of energy it can "borrow" during this time in MeV? (18.3 MeV)
15. An electron has an uncertainty in its velocity of ±2.10x104 m/s. What is the minimum uncertainty in its position? (1.38x10-9 m)
16. An electron has an uncertainty in its position of 2.40x10-10 m (total range) . What is the minimum uncertainty (the total range) of its velocity? (2.41x105 m/s)
17. A proton has an uncertainty in its position of 3.51x10-15 m (total range). What is the minimum uncertainty (the total range) of its velocity? (8.98x106 m/s)
18. A proton has an uncertainty in its velocity of ±4.30x106 m/s. What is the minimum uncertainty in its position? (3.66x10-15 m)
Particle Physics:
Part A:
Part B:
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