PHYS 3310 Module 13 Self Assessment Practice Problems

Module 13 Self Assessment Practice Problems

13.1
249Cf undergoes alpha decay.
(a) Write the reaction equation.
(b) Find the energy released in the decay.
Answer: (b) 6.29 MeV
13.2
Show that the alpha-emission process 226Ra –> 222Rn + 4He is energetically possible, and calculate the kinetic energy of the emitted alpha particle. The neutral atomic masses are 226.025410 u for 226Ra, 222.017578 u for 222Rn, and 4.002603 u for 4He.
Answer: 4.87 MeV
13.3
The nuclide 60Co, an odd-odd unstable nucleus, is used in medical and industrial applications of radiation. Show that it is unstable relative to negative beta decay. The atomic masses you need are 59.933817 u for 60Co and 59.930786 u for 60Ni .
Answer: 2.82 MeV
13.4
The nuclide 57Co is an odd-even unstable nucleus. Show that it cannot undergo positive beta decay, but that it can decay by electron capture. The atomic masses you need are 56.936291 u for 57Co and
56.935394 u for 57Fe .
Answer: -0.187 MeV, 0.835 MeV
13.5
Write the complete decay equation in the complete  notation for the beta (𝛽−) decay of 3H (tritium), a manufactured isotope of hydrogen used in some digital watch displays, and manufactured primarily for use in hydrogen bombs.
Answer:
13.6
A rare decay mode has been observed in which 222Ra emits a 14C nucleus.
(a) The decay equation is 222Ra → 𝐴X + 14C. Identify the nuclide 𝐴X.
(b) Find the energy emitted in the decay. The mass of 222Ra is 222.015353 u.
Answer: (b) 33.03 MeV
13.7
What mass of 235U must undergo fission each day to provide 3000 MW of thermal power?
Answer: 3.2 kg
13.8
(a) Calculate the energy released in this rare neutron-induced fission 𝑛 + 238U → 96Sr + 140Xe + 3𝑛, given 𝑚(96Sr) = 95.921750 u and 𝑚(140Xe) = 139.92164 u.
(b) This result is about 6 MeV greater than the result for spontaneous fission. Why?
(c) Confirm that the total number of nucleons and total charge are conserved in this reaction.
Answer: (a) 177.1 MeV
13.9
Two deuterons fuse to form a triton (a nucleus of tritium, or and a proton. How much energy is liberated?
Answer: 4.03 MeV
13.10
During a diagnostic x-ray examination, a 1.2-kg portion of a broken leg receives an equivalent dose of 0.40 mSv.
(a) What is the equivalent dose in mrem?
(b) What is the absorbed dose in mrad and in mGy?
(c) If the x-ray energy is 50 keV, how many x-ray photons are absorbed?
Answer: (a) 40 mrem (b) 40 mrad, 0.40 mGy (c) 6.0 x 1010