A.0 B.4.625×106Bq C.9.25×106Bq D.1.85×107Bq E.2.775×107Bq
A.λ=0.693·T1/2 B.T1/2=0.693·λ C.λ·T1/2=0.693 D.T1/2-λ=0.693 E.T1/2+λ=0.693