Answer to Question #258423 in Atomic and Nuclear Physics for Megg

Question

 The half-life of strontium-91, 91

38Sr is 9.70 h. Find 

(a) its decay constant, and

(b) for an initial 1.00-g sample, the activity after 15 hours. 

Answer 1

a)

$\lambda=\frac{\ln 2}{T_{1/2}}=19.8\cdot 10^{-6}~s^{-1},$

b)

$A=\lambda \frac mM N_A 2^{-\frac t{T_{1/2}}}=44.8\cdot 10^{15}~Bq.$