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A certain radioactive material is known ...

A certain radioactive material is known to decay at a rate proportional to the amount present. Initially there is 50 kg of the material present and after 2h it is observed that the material has lost 10 percent of its original mass. Based on these data answer the following questions.
The time at which the material has decayed to one half of its initial mass is

A

`50^(-0.5" ln "9)`

B

`50e^(-2" ln "9)`

C

`50e^(-2" ln "0.9)`

D

None of these

Text Solution

Verified by Experts

The correct Answer is:
C
We require N at t=4. Substituting t=4 into (3) and then solving for N, we find
`N=50e^(2" ln "0.9)`
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