Enter the initial quantity, final quantity, and total time passed to calculate the half-life. Half-life is defined as the time it takes for a value to decrease by half. This is most often used in nuclear physics.
Half-Life Formula
So, how do you calculate half-life? Half-life is calculated using the exponential decay formulas, as shown below.
- Where N0 is the initial quantity
- N(t) is the quantity remaining after some time
- t1/2 is the half-life, and t is time.
This can be further simplified into the following to calculate half-life.
What is half-life?
A half-life is the time it takes a given substance to deteriorate or lose half of its mass.
Half-life is a term mostly used in nuclear physics to describe the rate of decay of radioactive substances. As a result, the formula above includes the decay constant of the material. However, the half-life can also be calculated simply through time passed, initial quantity, and final quantity by re-arranging the very first equation above.
The idea of half-life is that since it’s exponential decay, it starts off losing a lot of mass to start, then slowly slows down. It will never actually reach absolute 0. Yet, of course, it would eventually approach an amount considered negligible.
How to calculate a half-life?
How to calculate a half-life?
- First, you must determine the initial quantity of your substance
For this example we will assume that to be 10 grams.
- Next, you need to measure the time that has passed.
For this example we will assume 10 seconds.
- Next, you need to measure the final quantity of substance
For this example we will assume 9 grams.
- Finally, plug the needed information into the formula
79.84 is the half life.
FAQ
Half-life is the time it takes a given substance to deteriorate or lose half of its mass.