The half life period of a radioactive elements does not depend upon:

Half-life period for radioactive element is

Half-life period for radioactive element is

The half life period of a radioactive element x is same as the mean life time of another radioactive element y. Initially they have the same number of atoms.Then :

The half life of radioactive element depends upon the

The half life period of a radioactive element is 90 minutes. What percentage of radioactive element will be present after 6 hours of decomposition ?