The half-life for the alpha decay of uranium 92238U2 is 6.45×109 yr. Determine the age (in years) of a rock specimen that contains sixty percent of its original number of 92238U atoms.
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Assuming that 6.45*10^9 y is correct, the age is found by
0.6 = 0.5^(t/6.45*10^9)
log0.6/log0.5 = t/6.45*10^9
log0.6/log0.5*6.45*10^9 = t
t = 4.753*10^9 y <---- age
OG
0.6 = 0.5^(t/6.45*10^9)
log0.6/log0.5 = t/6.45*10^9
log0.6/log0.5*6.45*10^9 = t
t = 4.753*10^9 y <---- age
OG