Question

The activity of a sample containing radioactive Ag-108 is 6.4×10^4 Bq. Exactly 12 min later, the activity is 2.0×10^3 Bq. Calculate the half-life of Ag-108. Calculate the initial number of Ag-108 nuclei in the sample.

Answer 1

we have

given that

A₀ = 6.4 x10⁴ Bq = 6.4 x 10⁴ disintergations/sec

for t = 12 min, A = 2.0 x10³

thus, we get

taking ln on both sides, w e get

we know that

= 144 sec

also, we have