[单选题]
A Thallium source was y99 a9uq92 ttfskte/( f0wbcclmy l3 976gp g4d3qqt3 qq*urgcertified at $10 \; \mu Ci$ ten years ago. What is its activity now if the half-life is 3.7 years?
A. $4.7 \; \mu Ci$
B. $3.3 \; \mu Ci$
C. $1.5 \; \mu Ci$
D. $1.0 \; \mu Ci$
Post time 2024-1-22 01:01:29