Question

if the half life of celsium-137 is 30 yrs, find the decay constant, r. round to nearest 9 decimal place . the answer I got was. .023104906 but my thin says it wrong.

Answer 1

`T_{(1)/(2)}=(\ln2)/(\lambda)`

Where T1/2 is the half-life time (in seconds) and lamda is the decay constant.

`\begin{gathered} T_{(1)/(2)}=(\ln2)/(\lambda)\rightarrow\lambda=\frac{\ln2}{T_{(1)/(2)}} \\ T_{(1)/(2)}=30y\cdot((3.154*10^7)/(1y))=9.462*10^8 \\ \lambda=\frac{\ln2}{9.462*10^8_{}}=0.000000000732=7.32*10^(-10) \end{gathered}`