It is 3.5 million years.
It is 11.2 years.
It is 252 days.
It is 12.33 years.
The half life of a radioisotope is the time taken for the number of radioactive atoms to decay to one-half. A free neutron has a half life of 10.6 minutes. The half life of carbon 11 is 20.3 minutes. Many isotopes have very short half lives, and many have very long ones.
This time is known as the half-life.
It depends on the radioisotope. They do not all have the same half life.
It is 11.2 years.
It is 252 days.
It is 432 years.
It is 2.6 years.
It is 15.02 hours.
It is 14.6 years.
It is 300,000 years.
It is 5.27 years.
It is 18.11 years.
It is 14.1 hours.
It is 7,380 years.