Exam 43: Nuclear Physics

A certain isotope has a half-life of 32.4 hr and a relative biological effectiveness of 3.50. A sample of this isotope initially delivers an absorbed dose of 0.240 Gy to 250 g of tissue. (a)What was the initial equivalent dose to the tissue in rem and in sieverts? (b)How many joules of energy did the 250-g sample initially receive from the isotope?

The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample,whereas the same amount of carbon from a piece of living wood produced 160 counts per minute.The half-life of carbon-14,a beta emitter,is 5730 y.The age of the artifact is closest to

The half-life of cobalt-60 is 5.3 years,while that of strontium-90 is 28 years.Suppose that samples of cobalt-60 and strontium-90 are such that they initially have the same activity (number of decays per second).What is true about the initial numbers of cobalt-60 and strontium-90 nuclei in these samples?

In the fission reaction U + neutron → Ba + Kr + x neutrons,what is the number x of neutrons produced?

In a laboratory accident a work area is contaminated with radioactive material.Health physicists monitor the area during a 30-day period and,after correcting for the background rate,obtain the data shown in the table. The accident occurred at t = 0.They determine that it will not be safe for workers to enter the area until the radioactivity level has dropped to 133 counts per minute.Of the choices listed below,which one is the earliest time that workers could safely return?

An archaeologist finds the ¹⁴C in a sample of of material to be decaying at 107 counts per second.A modern 1.00-g sample of the same material decays at 151 counts per second.The half-life of ¹⁴C is 5730 y.How old is the sample?

If a nucleus decays by gamma decay to a daughter nucleus,which of the following statements about this decay are correct? (There may be more than one correct choice.)

The stability of Sc with respect to alpha,β⁺,and β^- decay is to be determined.Do not consider the possibility of decay by electron capture.The following atomic masses are known: He: 4.002603 u K: 42.960717 u Ca: 46.954543 u Sc 46.952409 u Ti: 46.951764 u The Sc nuclide is

How does the mass of the products of a nuclear fusion reaction compare to the mass of the original elements?

An excited U^* nucleus undergoes fission into two fragments,as shown: U^* → Ba + Kr The following atomic masses are known: Kr: 91.926270 u Ba: 143.922845 u U^*: 236.045563 u What is the reaction energy,in MeV,for this process? (1 u = 1.6605 × 10^-27 kg =