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

Options

A. 62
B. 72
C. 82
D. 85

Answer

B

Explanation

Given : `(R_(Ge))/(R_(Be)) = 2`
But nuclear radius `R prop (A)^(1//3)`
`therefore (R_(Ge))/(R_(Be)) = ((A_(Ge))/(A_(Be)))^(1//3)`
`therefore ((R_G)/(R_B))^3 = (A_(Ge))/(A_(Be)) , " But " A_(Be) = 9`
`therefore (2)^3 = (A_(Ge))/(9) therefore A_(Ge) = 9xx2^3 = 72`
`therefore` Atomic mass number of Ge = 72
`therefore` Number of nucleons in Ge = 72