William Heathcote Solutions for Chapter: Patterns, Exercise 13: Exercise 13

At $9.00 \mathrm{AM}$, on a Monday, the activity of a sample of sodium$-24$ is measured to be $2400 \mathrm{Bq}$. By midday the following Thursday, the activity has fallen to $75 \mathrm{Bq}$. What is the half-life of Sodium$-24$?

A sample of uranium$-240$ has an activity of $20,480 \mathrm{Bq}$. After one week it has decayed until its activity is $5 \mathrm{Bq}$. What is the half-life?

Oganesson$-294\left({}_{118}{}^{294}\mathrm{Og}\right)$ was first synthesised in $2002$. It has a half-life of $0.7 \mathrm{ms}$. What is the probability of an atom of Oganesson last more than $3.5 \mathrm{ms}$?