The radioisotope sodium-24, half-life 15 h, is used to measure
the flow rate of salt water by irradiation of stable ?? with
neutrons, suppose that we produce 5 micrograms of the
isotope.
How long after a sample is placed in a reactor is it before the
sample activity reaches 75% of the maximum activity? Assume the
production of a single reactive species at a constant rate R sec-1,
the decay rate λ, and there is no initial activity in the
sample.
We use the equation:
A = A0 * 2-t/t0.5 , here A is the activity at time t ( 75% of A), A is the initial activity (A0), t0.5 is the half life
Using the values: 0.75 * A0 = A0 2-t/15
0.75 = 2-t/15
Solving, t = 6.22 Hours
The radioisotope sodium-24, half-life 15 h, is used to measure the flow rate of salt water...
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