Uranium ores contain one radium 226 atom for every 2.8 x 106 uranium 238 atoms. Calculate the half-life ofU 92238 given that the half-life of R 88226a is 1600
years (R 88226ais a decay product of U 92238)
175 x106 years
1600 x23892 years
4.5 x 109 years
1600 years
at steady state N1λ1=N2λ2 2.8 x1061T1=11T2 T2= 1600 years T1= 4.45 x 109