Question

What is the half-life of a radioisotope

Answer 1

The rate at which a radioactive isotope decays is measured in half-life. The termhalf-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Half-lives for various radioisotopes can range from a few microseconds to billions of years.

Answer 2

Answer:

It is the time after which a given sample of radioactive substance will decay to half of the initial number present in the sample.

Explanation:

As we know that as per law of radioactivity the number of radioactive nuclei present in the sample is proportional to the rate of decay

so it is given by

$\frac{dN}{dt} = -\lambda N$

after solving above relation we will have

$N = N_0e^{-\lambda t}$

now here we know that as the number of nuclei is reduced to half of the initial number then we have

$\frac{N_0}{2} = N_0e^{-\lambda t}$

$t = \frac{ln2}{\lambda}$

so this time is known as half life where the denominator of the equation is known as decay constant.