After a certain lapse of time, fraction ...

After a certain lapse of time, fraction of radioactive polonium undecayed is found to be `12.5%` of the initial quantity. What is the duration of this time lapsed if the half life of polonium is 138 days ?

A

`414` days

B

`407` days

C

`421` days

D

`410` days

Text Solution

Verified by Experts

The correct Answer is:

A

`(dN)/(dt)=lambda N`, here `N="avagadrono"//238, lambda=0.693//T_((1)/(2))`

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