According to radioactive decay law N=N0e−λt where N0= Number of radioactive nuclei at time t=0 N = Number of radioactive nuclei left un decayed at any time t λ= decay constant At time t2,
2
3
of the sample had decayed ∴N=
1
3
N0 ∴
1
3
N0=N0e−λt2.......(i) At time t1,
1
3
of the sample had decayed ∴N=
2
3
N0 ∴
2
3
N0=N0e−λt1.......(ii) Divide (i) by (ii), we get
