Radioactivity

Question 1

What does the decay constant represent?

Answer 1

The probability of a radioactive nucleus decaying per unit time.

Question 2

What equation links half-life and decay constant?

Answer 2

t{1/2} = ln2/λ

Question 3

What equation describes the relationship between a variable, the initial value of this variable and time when the variable is activity, count rate or number of undecayed nuclei left?

Answer 3

X=Xo e^-λt

Question 4

Define half-life.

Answer 4

The time for half of the radioactive nuclei to decay.

Question 5

Define activity.

Answer 5

The number of nuclei decaying per unit time (Becquerels).

Question 6

Describe how we obtain Technetium 99 for medical use.

Answer 6

Molybdenum 99 beta minus decays into Technetium 99 in a meta-stable state in which it remains for about 6 hours. After this the Technetium 99 moves into its excited state, and when it moves down to its ground state it releases a gamma photon.