Question

Find the half life of a radioactive natural which decays to 6.25% of it's original no. of nuclei in 50 seconds.

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Answer 1

After 1 decay it has .9375 of its value left

.9375^n = 1/2

What is the value of n (number of decays)

n log .9375 = -.693

n =.693 / .0645 = 10.7

After 10.7 periods of 50 sec it will have 1/2 of its original nuclei left

1/2 life = 10.7 * 50 sec = 537 sec = 8.95 min