1 mg gold undergoes decay with 2.7 days half- life period amount left after 8.1 days is
0.91 mg
0.25 mg
0.5 mg
0.125 mg
N=N012n⇒N=N012t/T1/2 ⇒N=1 x 128.12.7=123=18 ⇒N=18mg=0.125 mg