The half life period of radioactive element is 14 hours. What is the fraction of radioactive element that disintegrates in 56 hours?

Asked by Kaushik Gambhir | 31st Jul, 2010, 12:00: AM

Expert Answer:

If we begin with say 100gms of the given radioactive element,we will be left with 1/2 of it after 14 hours i.e. 50 gms
After another 14 hours (that is 28 hours) we will be left with 25 grams
After another 14 hours (that is 42 hours) we will be left with 12.5 grams
After the next 14 hours (that is 56 hours) we will be left with 6.25 grams
So in 56 hours we are left with 6.25 grams or 6.25/100 of original i.e 1/16
Since 56 hours mean 4 half lives the fraction left is  ½4

Answered by  | 31st Jul, 2010, 04:19: PM

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