The number of `alpha-` particles emitted per second by `1g` of `Ra^(226)` is `3.7 xx 10^(10)`. The decay constant is

Options

A. `1.39xx10^(-11)s^(-1)`
B. `13.9 xx10^(-11)s^(-1)`
C. `139xx10^(-11)s^(-1)`
D. `0.139xx10^(-11)s^(-1)`

Answer

A

Explanation

`(Number of at oms d i s i ntegrati ng per se c o nd )/(Total n umber of at oms present)=K`
or `(3.7xx10^(10))/((6.02xx10^(23))/(226))=(226xx3.7xx10^(10))/(6.02xx10^(23))=K`