Chemical Engineering - Nuclear Power Engineering - Discussion

27. 

75% of a radioactive element decays in 6 hours. Its half life period is __________ hours.

[A]. 3/4
[B]. 1/6
[C]. 3
[D]. 4

Answer: Option C

Explanation:

No answer description available for this question.

Colossus said: (Jul 5, 2017)  
I think the answer is 4. If 75% decay in 6hrs. 1% will decay in 6/75 hours and 50% will decay in 50*6/75 hrs= 4hrs.

Abir said: (Aug 11, 2017)  
0.25a=ae^6k,
ln0.25=6k
k=-0.23,
again, 0.5a=ae^-0.23t,
ln0.5=-0.23t,
t=3.

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