# The half-life of a certain radioactive isotope is 6 hours. If we start out with 100 grams of the isotope, how many grams will be left after 1 day?

##### 1 Answer

Apr 20, 2018

For half life the best way to go about it is to follow the general half life equation:

Where n is the half life time, in this case 6 hours and t is the time elapsed.

This equation can be better understood by understanding its mechanism: half of the initial mass will remain when you raise .5 to the power of 1, which means that when t=n, the power will be 1 and half the initial amount will be present.

Your initial mass is 100 grams, your half life time is 6 hours, and your time elapsed is 1 day or 24 hours. (Make sure your time elapsed is the same units as the half life time)

Putting all these in yields

Your mass is 6.25 grams after 24 hours.