Question

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Q. A sample of radioactive substance shows an activity of 3.4 millicurie and after 600 seconds the activity shown is 1.7 millicurie. What is the half-life of radioactive sample

1) 630 seconds
2) 693 seconds
3) 69.3 seconds
4) 63 seconds

Answer 1

Explanation:

k = 2.303/t log ( initial activity/ final activity)

= 2.303/600 log (3.4/1.7)

=0.00767 / sec

half-life = 0.693/0.00767 = 90.35sec