The selling rate of a radioactive isotope is decided by its activity. What will be the second-hand rate of a one month old 32P (t1/2 = 14.3 days) source if it was originally purchased for 800 rupees?
Given, t1/2 = 14.3 days
⇒The disintegration rate, s-1
t = 1 month = 30 days
A˳ = 800 disintegrations/sec
According to Law of Radioactivity, rate of disintegration of a radioactive isotope at time t will decay exponentially with rate of disintegration initially.
So,
disintegrations/sec
Hence, selling rate will be 187 rupees.