Solutions for Chapter 13: Nuclear Interactions and Applications

13.1) Rutherford was able to initiate nuclear reactions with particles before 1920. Why wasnt he able to initiatenuclear re...

13.2) In Example 13.2 we learned that the 12C(, n)15Ocross section is much larger than the 12C(, p)15N reactionfor E 14.6 M...

13.3) Why do the lifetimes of nuclear excited states decreasefor higher excitation energies?

13.4) Why is the density of nuclear excited states larger forhigher excitation energies?

13.5) Both deuterons and alpha particles can cause directreactions by stripping. Which are more effective?Explain.

13.6) Discuss the changes in the cross section for neutroninducedand proton-induced reactions as the initialkinetic energy ...

13.7) Think about how a chain reaction could be controlledwithout delayed neutrons. Is it possible? What wouldbe the diffi ...

13.8) Think carefully about the fi ssion process. Does it seempeculiar that symmetric fi ssion is not the most probable?Doe...

13.9) Why is it useful to slow down neutrons produced byfi ssion in a nuclear reactor?

13.10) All the moderators mentioned in this chapter to slowdown neutrons are light nuclei. Why are light nucleiused for mode...

13.11) Why is fi ssion fuel placed in 4-m-long rods placedparallel but separated, rather than in one lump ofmass?

13.12) Discuss how each of the following sources of energy isultimately derived from the sun: wood, coal, gas, oil,water, an...

13.13) Why does a stars temperature increase as fusion proceeds?Why are higher temperatures required for thecarbon cycle tha...

13.14) The fusion process continues in a very massive staruntil its core consists of nuclei near 56Fe. Explain whythis occurs.

13.15) The fi rst wall of a magnetic fusion containment vesselhas been said to contain the most hostile environmentyet desig...

13.16) Neutron-activation analysis is much more widely usedthan charged-particle activation. Why do you supposethat is true?

13.17) Explain in your own words the origin of the names ofelements 97 through 102; that is, who or what the elementswere na...

13.18) Explain in your own words the origin of the names ofelements 103 through 108that is, who or what theelements were nam...

13.19) Explain in your own words the origin of the namesof elements 109 through 114that is, who or whatthe elements were nam...

13.20) How many new elements have been discovered thatare not mentioned in this textbook? Discuss them.

13.21) Small research nuclear reactors, like those mostlyused in universities, are often submerged in concretestructures tha...

13.22) A common fi ssion fragment is 90Sr. Why is this isotopeconsidered particularly dangerous to human health?

13.23) The fi rst excited state of 17F is at 0.495 MeV. Can thep 16O reaction populate this state? Give yourreasons.

13.24) 239Pu absorbs a thermal neutron, and the resultingnucleus gamma decays to the ground state. (a) Whatis the energy of ...

13.25) List as many nuclear reactions as you can that usedeuterons and alpha particles for projectiles with stabletargets th...

13.26) Calculate how much energy is released when 239Pu absorbsa thermal neutron and fi ssions in the reactionn 23994Pu S 24...

13.27) A sample of shale contains 0.055% 238U by weight.Calculate the number of spontaneous fi ssions in oneday in a 106-kg ...

13.28) Calculate the percentage abundance of 235U and 238U2.0 billion years ago if the abundance today is 0.72%and 99.3%, re...

13.29) Use the information in Figure 13.8 to write at leastthree common sets of fi ssion fragments for the fi ssionproducts ...

13.30) A fi ssion reactor operates at the 1250-MWe level. Assumeall this energy comes from the (average) 200 MeVreleased by ...

13.31) Calculate the energy released in kilowatt hours fromthe fi ssion of 1.0 kg of 235U. Compare this with theenergy relea...

13.32) In his book Great Ideas in Physics, Alan Lightman estimatedthat the energy (all forms, not just electrical)needed for...

13.33) In 2011 one estimate of worldwide proven oil reserveswas 2.0 1011 m3. Using the data in Table 13.1, answerthe followi...

13.34) Neutrons in equilibrium with their surroundings attemperature T are called thermal neutrons and havean average kineti...

13.35) Determine the ground-state Q values for each of thereactions in the carbon cycle and show that the overallenergy rele...

13.36) There is a bottleneck in producing masses higherthan 4He, because there are no mass-5 or mass-8 stablenuclides. For o...

13.37) Following the triple-alpha process to form 12C (seethe previous problem), a variety of nuclear reactionscan form heav...

13.38) One of the fusion reactions that goes on in massivestars is silicon burning, 28Si 28Si S 56Ni . Thisreaction is how f...

13.39) One of the fusion reactions that goes on in massive starsis carbon burning, 12C 12C S 24Mg . (a) Calculatethe ignitio...

13.40) Assume that two thirds of Earths surface is coveredwith water to an average depth of 3 km. Calculate howmany nuclei o...

13.41) The ignition temperature of fusion reactions is referredto in both temperature and kinetic energy. (a) Explainwhy thi...

13.42) The following reactions may be useful in producingenergy for fusion reactions. Find their Q values. 4He(3He, )7Be, 2H...

13.43) Determine how hot the environment must be for thefi rst reaction of the CNO cycle to occur. (Hint: Firstfi nd the thr...

13.44) One of the possibilities for producing energy in a starafter the hydrogen has burned to helium is 3 S 12C(that is, th...

13.45) For a thermal neutron (300 K), fi nd its (a) energy,(b) speed, and (c) de Broglie wavelength.

13.46) To determine the wear of an automobile engine, asteel compression ring is placed in a nuclear reactor,where it become...

13.47) (a) Why does a 99mTc generator need to be shippedonce a week to hospitals? (b) What is the activity of a1011-Bq 99mTc...

13.48) The Los Angeles County Police want to use neutronactivation analysis to look for a tiny residue of bariumin gunpowder...

13.49) A 5.0 105 Bq 241Am alpha source is used in a smokealarm. The device is arranged so that 15% of the decayalphas are de...

13.50) Consider a spacecrafts power source consisting of210Po, which emits a 5.3-MeV alpha particle, t1/2 138days. (a) How m...

13.51) A hospital has a 3.0 1014 Bq 60Co source for cancertherapy. What is the rate of rays incident on a patientof area 0.3...

13.52) Rework Example 13.10 if the neutron is to probe thediameter of a 238U nucleus. Could neutrons from anuclear reactor b...

13.53) Assume that a 10.0-kg sample of 239Pu is used to produceelectrical power from its decay. If your deviceis 60% effi ci...

13.54) We mentioned several superheavy elements that hadbeen observed but not yet confi rmed or offi ciallyapproved by the I...

13.55) An infl ated catheter is used in balloon angioplasty toopen up arteries that are occluded with plaque formation.Stent...

13.56) In a nuclear reactor, the effective cross section for thermalneutrons in uranium is the weighted average of thecross ...

13.57) A thermal neutron induces fi ssion in a 235U nucleus.One of the fi ssion products is 132Sn, and three freeneutrons ar...

13.58) Compare the following: (a) total atomic binding energyof 1.0 kg of hydrogen atoms, (b) nuclear bindingenergy of 1.0 k...

13.59) One method used to determine unknown atomicmasses consists of precisely measuring the kinetic energiesof the particle...

13.60) 90Sr is one of the most deadly products of nuclear fi ssion.Assume that 4% of the fi ssion fragment yieldfrom a 235U ...

13.61) Assume a temperature of 2.0 108 K in a controlledthermonuclear reactor. (a) Calculate the most probableenergy of deut...

13.62) A PuBe source has a neutron activity of 1.6 105 Bq.The neutrons are produced by the 9Be(, n)12C reactionwith an effec...

13.63) A typical person of mass 65 kg contains 0.35% potassium,by weight. Of the potassium, 0.012% is 40K, anunstable nucleu...

13.64) The yields of nuclear fi ssion bomb weapons are measuredin terms of the equivalent amount of energyproduced by 1 kilo...

13.65) The rate of spontaneous fi ssion in 238U is 6.7 decaysper second for each kg of uranium present. The remainingdecays ...