What is the mass of 1 curie of `""_(27)C^(60)` ? Half life of `""_(27)C^(60)` is 5.25 years:

Options

A. `8.8 xx 10^(-6)kg`
B. `8.8 xx 10^(-7)kg`
C. `8.8 xx 10^(-8)kg`
D. `8.8 xx 10^(-9)kg`

Answer

B

Explanation

`R=(d N)/(dt) =lambda N =3.7 xx 10^(10) //sec`.
`N=(3.7 xx 10^(10))/(lambda)=(3.7 xx 10^(10) xx T)/(0.693)`
`=(3.7 xx 10^(10) xx 5.25 xx 3.16 xx 10^(7))/(0.693)`
`=8.85 xx 10^(18)`
Mass of N atoms `=(60 xx 8.85 xx 10^(18))/(6.02 xx 10^(26)) kg`
`=8.8 xx 10^(-7)kg`