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Two radioactive substance A and B have d...

Two radioactive substance `A` and `B` have decay constants `5 lambda` and `lambda` respectively. At `t=0` they have the same number of nuclei. The ratio of number of nuclei of nuclei of `A` to those of `B` will be `(1/e)^(2)` after a time interval

A

`(1)/(2 lambda)`

B

` (1)/(4 lambda)`

C

` 4 lambda`

D

` 2 lambda`

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The correct Answer is:
A
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