The half-life of a radioactive nucleus is 5 years. The fraction of the original sample that would decay in 15 years is :

Step-by-step solution

The formula to calculate the number of half lives covered by the radioactive material is given by n = t T 1 2       . . . 1 Substitute the values of the known parameters into equation (1) to calculate the number of half lives covered. n = 15   years 5   years =   3 The relation between the amount of radioactive substance after certain time can be written as N = N 0 2 - n       . . . 2 Substitute the value of n into equation (2) to obtain the fraction of the remaining sub