Question

Question -The half life period of a radioactive element is 140 days.After 560 days, one gram of the element will reduce to

Answer 1

Let n is equal to the ratio of total time and half-life period, which is 
n=Total time / Half-life period = 560/140 =4. 
To determine the element reduction, 
N = N0(1/2)n 
N = N0(1/2)4 
N = N0/16 
N0 = 1 gram 
Therefore, one gram of the element will reduce to 1/16 of the original amount.