Exam 29: Nuclear Physics

One material used in nuclear bombs is ²³⁹Pu,with a half-life of 24,000 years.How long must we wait for a buried stockpile of this substance to decay to 1/1000 of its original activity?

A nuclear reaction is shown: 10 5 B + ${}^{4}_{2}$ He → ${}^{1}_{1}$ H + ? .Which one of the following isotopes is the missing nuclear product?

The diameter of an atom is 1.4 × 10^-10 m and the diameter of its nucleus is 1.0 × 10^-14 m.What fraction of the atom's volume is occupied by its nucleus?

In the fission reaction ²³⁵U + ¹n → ¹⁴¹Ba + ⁹²Kr + x ¹n,what is the number x of neutrons produced?

During β^- decay

Determine the missing product X in the nuclear reaction $^{238}_{92} U$ + ${}^{1}_{0}$ n → X + 2β^-.

A radioactive substance containing 4.0 × 10¹⁶ unstable atoms has a half-life of 2.0 days.What is its activity (in curies,Ci)after 1.0 day? (1 Ci = 3.70 × 10¹⁰ Bq)

The radius R of a nucleus of mass number A is given by R = R₀ A^1/3,where R₀ = 1.2 × 10^-15 m,calculate the density of a nucleus that has contains 57 protons and 82 neutrons.The mass of a nucleon (proton or neutron)is 1.67 × 10^-27 kg.

A sodium-22 nucleus, ${}^{22}_{11}$ Na,decays into a neon-22 nucleus, ${}^{22}_{10}$ Ne,and one other particle.What is the other particle?

What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.)

Modern in-air nuclear bomb tests have created an extra high level of ¹⁴C in our atmosphere.If future archaeologists date samples from this era,without knowing of this testing,will their carbon-14 dates be too young,too old,or correct? If correct,why?

The maximum permissible workday dose for occupational exposure to radiation is 18 mrem.A 54-kg laboratory technician absorbs 2.6 mJ of 0.30-MeV gamma rays in a work day.The relative biological effectiveness (RBE)for gamma rays is 1.00.What is the ratio of the equivalent dosage received by the technician to the maximum permissible equivalent dosage?

In a ${}^{93}_{41}$ Nb nucleus,how many protons,neutrons,and electrons are found there?

A β^- decay occurs in an unstable nucleus when

A sample of wood has been recovered by an archaeologist.The sample is sent to a laboratory,where it is determined that the activity of the sample is 0.144 Bq/g.By comparing this activity with the activity of living organic matter,which is 0.230 Bq/g,the scientist determines how old the wood sample is,or more precisely,when the tree that the sample came from died.Carbon-14 has a half-life of 5730 years.If the activity of living matter has been constant over time,how old is the sample of wood?

The radioactivity due to carbon-14 measured in a piece of a wooden casket from an ancient burial site is found to produce 20 counts per minute from a given sample,whereas the same amount of carbon from a piece of living wood produces 160 counts per minute.The half-life of carbon-14,a beta-minus emitter,is 5730 years.What would we calculate for the age of the artifact,assuming that the activity for living wood has remained constant over time?

Isotope A has a decay constant of 0.723 s^-1 and isotope B has a decay constant of 0.514 s^-1.Which isotope has a longer half-life?

An yttrium isotope has 39 protons and 50 neutrons in its nucleus.Which one of the following symbols accurately represents this isotope?

Write the standard nuclear notation for the following nuclei: hydrogen-2,sulfur-33,and lead-207.

When a stationary plutonium-239, $^{239}_{94} Pu$ ,decays into uranium-235 plus an alpha particle,the energy released in the process is 5.24 MeV.The following masses are known: ${}^{4}_{2}$ He: 4.002603 u $^{235} _{92} U$ : 235.043924 u What is the mass of the $^{239}_{94} Pu$ nucleus,in amu? (1 u = 931.494 MeV/c²)