6. The radioactive isotope (191 Pt) has a half-life of 2.86 days. A sample containing this isotope has an initial activity at (t = 0) of 4.50 x10³ Bq. Calculate the number of nuclei that will decay in the time interval between t₁ = 38.0 hours and t2 = 65.0 hours. nuclei

Madame Curie filled glass vials with pure radon, produced by her radium, for use in hospitals. Radon has a short half-life of 3.8 days. Suppose that she put 1 MBq of radon in a vial. i) Sketch a graph of the activity of the radon over the next week or two. Label the axes with appropriate numbers and units. Mark on the graph the half-life and the characteristic time. ii) Radon decays through a chain of four very short-lived radionuclides (halflives of 20 minutes and less) before reaching a relatively stable isotope of lead. Approximately what activity will the vial have two or three hours after filling, and about two weeks after filling?

3. The following graph shows the amount of mg for a radioactive substance. a. Determine the initial quantity of the material. b. Determine the half-life for this substance. 200 180 160 140 120 100 80 60 40 20 c. Determine the percent decrease per hour. d. Determine how long it will take for only 25 mg of the substance to remain. 10 (12,50) 15 20 25 30 W 35 40

48. The mass of a nucleus of plutonium (Pu23994) is 238.990396 u. Show that the binding energy per nucleon for plutonium is 7.6 MeV (show your work on scratch papers). A radioactive isotope of an element decays with half-life 10 minutes. If originally there are 64 atoms in a sample of the element, what is the time that should pass until only one atom of the element is left out? What is the decay constant k?