An element X has a half life of 12.5 yr. Initially, it has N nuclei in its sample. How much of the sample is decayed after 25 yrs?
Answer & explanation
Correct answer: option 1
After 12.5 yrs, half the sample will be decayed and half will be left.
Sample decayed : N/2
Sample remaining : N/2
After another 12.5, half the sample will be decayed and half will be left.
Sample decayed :\(\frac{1}{2}\) (N/2) = N/4
Sample remaining : \(\frac{1}{2}\) (N/2) = N/4