Half life of a radio-active substance is 20 minutes. The time between – McqOptions

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1.	Half life of a radio-active substance is 20 minutes. The time between 20% and 80% decay will be [KCET 2003]
A.	20 minutes
B.	40 minutes
C.	30 minutes
D.	25 minutes
Answer» C. 30 minutes

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