What is meant by the half-life of a radioactive substance

The half-life of a radioactive substance is the time the substance takes to be reduced by half of its initial amount as a consequence of decay.

Explanation:

The half-life of a radioactive substance is the time the substance takes to be reduced by half of its initial amount as a consequence of decay.It is a characteristic constant.It is known that the decay of a radioactive isotope isotope obeys first order kinetics.Also, it is clear that in first order decay the half-life time is independent of the initial concentration.