Q. Describe the Half -Life  property of radioactive decay?

Ans.

The decay of a nucleus is a random event. It is impossible to predict which nucleus will decay and when. Over a period of time, though, the decay rate is constant which allows us to predict when a given fraction of the sample has decayed.

The half-life is the amount of time it takes for half of a chunk of radioactive isotope to undergo radioactive decay. It is usually denoted by the symbol t_1/2.

The half-life of germanium-69 is 36 hours. If we start with n atoms of , then at the end of 36 hours we will have n/2 (half) of the atoms of left. The rest of the atoms will have changed into another element or isotope. At the end of the next 36 hours (that's 72 hours from the starting point) there will be n/4 atoms of left. After another 36 hours have passed (108 hours from the beginning) there will be n/8 atoms. See the trend? After each half-life we have half of the previous amount.