True or false: the amount of a radioactive element remaining in an object its measured. based on the known half life of the element the amount remaining can be used to calculate how old the object is.

True

Explanation:

All radioactive element have a specific property of reducing itself by half of its actual amount in a certain period of time.

Suppose, an element X has a half life of 3 years. This means that this element "X" will reduce its quantity by half after every three years.

Now , if a case in given in which it is specified that some "Y" grams of element "X" is found and the age of the substance in which this element "X" is found is to be determined.

Then by the under given relation the age of substance containing element X can be determined

Where "N" is the inital mass or atomic mass of X

N0 is the present mass of X

t is the age of substance

and is the decay constant i.e half life