Question

Question

Answer 1

Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Show all calculations leading to a solution.

Answer 2

@tkhunny

Answer 3

25% is one half and then one half again.

Answer 4

25=100 e^(-.693 t/45.1)


Ln(25)=ln(100) -.693 t/45.1
ln(25)-ln(100)=-.693 t/45.1
ln(25/100)=-.693t/45.1

t= - 45.1/.693 ( ln .25)


t=90.2 days?

Answer 5

@ganeshie8 @Compassionate @Nnesha Is this right?

Answer 6

100 ==> 50 in 45.1 days.
50 ==> 25 in 45.1 days.