A radioactive isotope has a half life of 5 years. How long will it take the activity to reduce to 3.125%?
mean life = 1.44 * T1/2 = 1.44 * 5 = 7.2 Years
Given N/N0 = 3.125% = 3.125/100 = 1/ 32
But N/N0 = (1/2)n
therefore, 1/ 32 = (1/2)n
(1 /2)5 = (1/2)n
n=5
time taken = 5 * 5 =25 years
Given N/N0 = 3.125% = 3.125/100 = 1/ 32
But N/N0 = (1/2)n
therefore, 1/ 32 = (1/2)n
(1 /2)5 = (1/2)n
n=5
time taken = 5 * 5 =25 years