How do I find the half-life of radioactive isotope?

The half-life of a radioactive isotope is the time taken for half of the atoms in a given sample of the isotope to decay. Radioactivity is random and so, half-life is the average time taken for a large number of atoms. 

There are two ways to find the half-life, both come from the decay equation:   N = N0e^(-λt)      which is an exponential relationship*. 

Where N is the number of atoms of the isotope left at time t and Nis the number of atoms when t =0. λ is known as the decay constant and is the probability that an atom will decay per unit time. If you are given the decay constant you may find the half-life T1/2 by setting N = N0/2 and rearranging to find t = T1/2. Or if you are given N and Nyou may find λ and follow the previous steps.

*Make sure you familiar with exponentials and logs before attempting this topic

JS
Answered by Joe S. Physics tutor

14419 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Why does the Photoelectric Effect lead to the conclusion that classical physics cannot be all of physics?


Compare and contrast geostationary and low polar orbits.


What is an electron volt?


A cricketer throws a ball vertically upwards so that the ball leaves his hands at a speed of 25 m/s. Calculate the maximum height reached by the ball, the time taken to reach max. height, and the speed of the ball when it is at 50% max. height.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences