Putting these values in equation (iii), we get
Thus it is evident that t1/2 of an element does not depend on the initial amount of radioactive element but depends on the value of l.The t1/2 of a particular radioactive isotope is a characteristic constant of that isotope. Values of t1/2range from millions of years
The disintegration rate is also referred to as activity. The SI unit of radioactivity is becquerel (Bq) named after Antoine Becquerel, which is equal to one disintegration per second. The older unit, curie, named after Marie Curie is still used, One Curie (Ci) is defined as the amount of radioactive isotope that give 3.7 x 1010 disintegrations per second. This is the activity associated with 1g of radium-225 with half - life of 1600 years).Thus 1 Ci = 3.7 x 1010 disintegration s-1
= 3.7 x 1010 Bq.