A radioactive sample is monitored with a radiation detector to produce 7640 counts per minute. Twelve hours later, the detector reads 1410 counts per minute. 1) Calculate the decay constant of the sample. (Express your answer to two significant figures.) 2) Calculate the half-life of the sample. (Express your answer to two significant figures.)

What is the dose in mSv for: (a) a 0.1-Gy X-ray? (b) 2.5 mGy of neutron exposure to the eye? (c) 1.5m Gy of a exposure?

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.

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

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

How many Gy of exposure is needed to give a cancerous tumor a dose of 40 Sv if it is exposed to a activity?

If a 1.50cmthick piece of lead can absorb 90.0% of the rays from a radioactive source, how many centimeters of lead are needed to absorb all but 0.100% of the rays?

In the following eight problems, write the complete decay equation for the given nuclide in the complete XZAN notation. Refer to the periodic table for values of Z. decay of 226Ra, another isotope in the decay series of 238U, FIrst recognized as a new element by the Curies. Poses special problems because its daughter is a radioactive noble gas. In the following four problems, identity the parent nuclide and write the complete decay equation in the XZAN notation. Refer to the periodic table for values of Z.