What is the activity of gram of55 Fe in curiesSolutionFor Fe

What is the activity of gram of^55 Fe in curies?

For Fe-55, half life = 2.737 years

lambda = ln(2) / 2.737 = 0.25325 / year

No of atoms = 6.022*10^23 / 55 = 1.094*10^22 atoms

Activity A = lambda*N

= 0.25325*1.094*10^22 atoms/yr

= 2.773*10^20 atoms/yr

1 year = 365*24*60*60 seconds = 31536000 seconds

Activity = 2.773*10^20 / 31536000 atoms/sec

= 8.793*10^12 atoms/sec

There is 1 decay/atom.

So decay rate = 8.793*10^12 decays/s

1 Ci = 3.7*10^10 decays/s

Decay rate = 8.793*10^12 / (3.7*10^10) = 237.65 Curies