the half life of colbalt-60 is approximently 5.25 days. find the amount of cobalt-60 left from a 30 gram sample after 42 days. round to the nearest thousandth of a gram.
+33654 The expression for radioactive decay is N = N0e-ln(2)t/th where N is the mass, at time t, N0 is the mass at the start (30grams) and th is the half-life (5.25days), so here:
N=30×e−(ln(2)×425.25)=N=0.1171875000000001 grams
To the nearest thousandth of a gram this is 0.117grams.
+33654 The expression for radioactive decay is N = N0e-ln(2)t/th where N is the mass, at time t, N0 is the mass at the start (30grams) and th is the half-life (5.25days), so here:
N=30×e−(ln(2)×425.25)=N=0.1171875000000001 grams
To the nearest thousandth of a gram this is 0.117grams.
