Question

A radioactive sample has a mass m, decay cosntant `lambda`, and molecular weight M. If the Avogadro number is `N_A`, then
(a) find the initial number of neclei present, (b) find the number of deacyed nuceli after a time t, (c ) find the activity of the sample after a time t,
A. `((mN_(A))/(M))e^(lambdat)`
B. `((mN_(A)lambda)/(M))e^(-lambdat)`
C. `((mN_(A))/(Mlambda))e^(-lambdat)`
D. `(m)/(lambda)(1-e^(-lambdat))`

Answer 1

Correct Answer - B
Activity `=lambdaN_(o)e^(-lambda t)` where `N_(o)=(N_(A)m)/(M)`