Question

Please answer based on nuclear activity and please identify the terms for question 1, part a and part b. Please answer the second part of the question, question 2 in an answer that matches the question correctly. I am re-posting these as they were answered incorrectly last time.

1. What terms identify

a) a radioactive material that, upon decay, results in another radioactive material?

b) the resulting radioactive material?

&

2. Under what conditions is secular equilibrium reached between the daughter and parent?

Answer 1

1.a) The radioactive material, known as parent material (parent radionuclide or parent radio isotope), upon decay, results in another radioactive material(nuclear transmutation).

1.b) The resulting radioactive material is known as daughter material (daughter nuclide, that may be a radio isotope). Daughter nuclides are generally found in exited state after creation. As a result of that daughters are most of the time radioactive in nature and go to ground state by emitting gamma photons or to some new daughter(s) by emitting alpha or beta.

2. Secular equilibrium is a situation in which the quantity of a radioactive isotope remains constant (not perfectly constant but almost constant) with time. Consider a radioactive process like A-> B->C where A and B are radionuclide. We can say radionuclide B is in secular equilibrium if buildup of B is equal to the decay of B. Secular equilibrium is achieved when half-life of B is much shorter (negligible) than half-life of A and a nonzero initial amount of B. As a result of it the buildup amount of B is decayed instantly due to B's short half-life and the amount of B remains constant with time. Rate of buildup of B is proportional to dacay rate of A. For equilibrium this must be equal to dacay rate B. Therefore condition for equilibrium for a short range of time in disintegration constant is where N_{​​​​​​A} and N_{​​​​​​B} are number of active nucli present at the time of equilibrium. As time goes amount of B decrease slowly and equilibrium hampered.