# What is the formula for radioactivity?

## What is the formula for radioactivity?

Average number of radioactive decays per unit time (rate) • or – Change in number of radioactive nuclei present: A = -dN/dt • Depends on number of nuclei present (N). During decay of a given sample, A will decrease with time.

How do you calculate radioactive nuclei?

The activity of 14C is determined using the equation A0=λN0, where λ is the decay constant and N0 is the number of radioactive nuclei.

### How do you calculate activity?

To find the activity R using the equation R=0.693Nt1/2 R = 0.693 N t 1 / 2 , we must know N and t1/2. The half-life of 14C can be found in Appendix B, and was stated above as 5730 y. To find N, we first find the number of 12C nuclei in 1.00 kg of carbon using the concept of a mole.

Formula: Radioactivity = (Mass of the element / Atomic mass of the element) x Avagadro’s constant x (ln (2) / Time) One becquerel (Bq) is defined as the activity of a quantity of radioactive material in which one nucleus decays per second, which is equivalent to inverse of a second, s -1.