Nuclei - Result Question 5
5. The radius of germanium $(Ge)$ nuclide is measured to be twice the radius of $ _4^{9} Be$. The number of nucleons in Ge are
[2006]
(a) 74
(b) 75
(c) 72
(d) 73
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Answer:
Correct Answer: 5. (c)
Solution:
- (c) We use the formula,
$R=R_0 A^{1 / 3}$
This represents relation between atomic mass and radius of the nucleus.
For berillium,
For germanium, $\quad R_2=R_0 A^{1 / 3}$
$\frac{R_1}{R_2}=\frac{(9)^{1 / 3}}{(A)^{1 / 3}} \Rightarrow \frac{1}{2}=\frac{(9)^{1 / 3}}{(A)^{1 / 3}}$
$\Rightarrow \frac{1}{8}=\frac{9}{A} \Rightarrow A=8 \times 9=72$.
