Question

The radius of a spherical nucleus as measured by electron scattering is $3.6 \,fm$. What is the likely mass number of the nucleus?

• A. $27$
• B. $40$
• C. $56$
• D. $120$

Answer 1

Answer: (A)

Nuclear radius $R=R_{0}\left(A\right)^{1/ 3}$
where $A$ is the mass number of a nucleus
Given : $R = 3.6\, fm$
$\therefore \, 3.6\,fm =\left(1.2\,fm\right)\left(A^{1 /3}\right) \left[\because\, R_{0}=1.2\,fm\right]$
or $A=\left(3\right)^{3}=27$