The stable nucleus that has a radius `1//3` that of `Os^(189)` is-

Options

A. `""_(3)Li^(7)`
B. `""_(2)He^(4)`
C. `""_(5)B^(10)`
D. `""_(6)C^(12)`

Answer

A

Explanation

Radius of `Os^(189) = r_(0) A_(Os)^(1//3)`
Radius of that nucleus
`= (1)/(3) xx r_(0) (A_(Os))^(1//3) = r_(0) ((189)/(27))^(1//3) = r_(0) 7^(1//3)`
`therefore` Mass number (A) for that nucleus = 7, i.e., stable nucleus = `""_(3)Li^(7)`.