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A sample of radioactive material has mas...

A sample of radioactive material has mass `m`, decay constant `lambda`, and molecular weight `M`. Avogadro constant `=N_(A)`. The initial activity of the sample is:

A

`lambdam`

B

`(lambdam)/M`

C

`(lambdamN_A)/M`

D

`mN_Alambda`

Text Solution

Verified by Experts

The correct Answer is:
c
Activity = number of disintegrations per unit time Activity =`|(dN)/(dt)|=lambdaN`
where N = the total number of nuclei
Also, N = number of moles x `N_A=(m/M)N_A`
`therefore ` Initial activity=`(lambda mN_A)/M`
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