Answer : The time it takes for 50 percent of the nuclei in a radioactive sample to decay to its stable isotope is called Half-life.
Explanation :
Half-life of radioactive isotope decay : It is defined as the rate at which a decay is measured in half-life. Or we can say that the time it takes for (1/2) half of the nuclei in a radioactive sample to decay to its stable isotope.
The radioactive isotope decay shows first order reaction. The formulas used for first order reaction is,
[tex]t_{1/2}=\frac{0.693}{\lambda}[/tex]
where,
[tex]t_{1/2}[/tex] = radioactive half-life
[tex]\lambda[/tex] = radioactive decay constant
Hence, the correct answer is, Half-life.
