The age of a piece of wood from an archeological site is to be determined using the Carbon-14 method. The activity of the sample is measured to be 0.58 times the Carbon-14 activity of living plants. What is the age of the sample in years? (The half-life of the Carbon-14 isotope is 5730 years.)

Data from the appendices and the periodic table may be needed for these problems. A 60Co source is labeled 4.00 mCi, but its present activity is found to be 1.85107Bq. (a) What is the present activity in mCi? (b) How long ago did it actually have a 4.00—mCi activity?

What fraction of a radioactive sample has decayed after two half-lives have elapsed?

Data from the appendices and the periodic table may be needed for these problems. Show that the activity of the 14C in 1.00 g of 12C found in living tissue is 0.250 Bq.

Which of the following is the correct daughter nucleus associated with the beta decay of 72184Hf? (a) 72183Hf (b) 73183Ta (c) 73184Ta

Does the number of radioactive nuclei in a sample decrease to exactly half its original value in one halflife? Explain in terms of the statistical nature of radioactive decay.

The atomic weight of cadmium is 112.41, and its density is 8.65 g/cm3. Using Figure 14.3, estimate the attenuation distance of a thermal neutron beam in cadmium. (The attenuation distance is the distance traveled after which the intensity of the beam is reduced to 1/e of its initial value, where e is the base of the natural logarithms.)

Which of the following is the correct daughter nucleus associated with the alpha decay of 72157Hf? (a) 72153Hf (b) 70153Yb (c) 70157Yb

If everyone in Australia received an extra 0.05 mSv per year of radiation, what would be the increase in the number of cancer deaths per year? (Assume that time had elapsed for the effects to become apparent.) Assume that there are 200104 deaths per Sv of radiation per year. What percent at the actual number of cancer deaths recorded is this?

Data from the appendices and the periodic table may be needed for these problems. (a) Calculate the activity R in curies at 1.00 g of 226Ra. (b) Discuss why your answer is not exactly 1.00 Ci, given that the curie was originally supposed to be exactly the activity of a gram of radium.