The radius of germanium `(Ge)` nuclide is measured to be twice the radius of `_(4)^(9)Be`. The number of nucleons in `Ge`

Options

A. 72
B. 73
C. 74
D. 75

Answer

A

Explanation

Nuclear radii `R = R_(0) (A)^(1//3)`, where `R_(0) ~~ 1.2` fm
or `R prop (A)^(1//3)`
`therefore" "(R_(Be))/(R_(Ge)) = ((9)^(1//3))/((A)^(1//3)) or, (R_(Be))/(2 R_(Be)) = ((9)^(1//3))/((A)^(1//3))" "(because "given" R_(Ge) = 2 R_(Be))`
or, `(A)^(1//3) = 2 xx (9)^(1//3)`
or, `A = 2^(3) xx 9 = 8 xx 9 = 72`
`therefore` The number of nucleons in Ge is 72.