91Ó°ÊÓ

In the final step of the uranium- 238 disintegration series, the parent nuclide decays into lead-206 and an alpha particle. Identify the parent nuclide.

The uranium- 235 decay series begins with the emission of an alpha particle. The daughter product emits a beta particle to give which nuclide?

In the final step of the uranium- 235 disintegration series, the parent nuclide decays into lead- 207 and a beta particle. Identify the parent nuclide.

What percentage of U-238 radionuclides in a sample remain after two half- lives?

What percentage of U-238 radionuclides in a sample remain after three half- lives?

A nuclear reactor produces spent Pu-239 fuel rods that are highly radioactive after they no longer support fission. If 15 half-lives are required for the nuclide to reach a safe level, how long must the rods be stored? \(\left(t_{1 / 2}=24,400\right.\) years \()\)

A nuclear fission reactor produces Sr-90 radioactive waste. If 20 half-lives are required for the nuclide to reach a safe level, how long must the nuclear waste be stored? \(\left(t_{1 / 2}=28.8\right.\) years \()\)

If the carbon-14 radioactivity of an ancient wooden artifact is \(6.25 \%\) that of a reference sample, what is the estimated age of the artifact? \(\left(t_{1 / 2}=5730\right.\) years \()\)

If the carbon- 14 reading of a fossil bone is \(60 \mathrm{dpm}\), and a recent bone is \(240 \mathrm{dpm},\) what is the estimated age of the fossil? \(\left(t_{1 / 2}=5730\right.\) years \()\).

Sodium- 24 in the form of \(\mathrm{NaCl}\) is given as an injection to measure the sodium electrolyte balance. If \(80 \mathrm{mg}\) of the medical radionuclide is injected, how much \(\mathrm{Na}-24\) remains after 60 hours? \(\left(t_{1 / 2}=15\right.\) hours \()\).