Question

Let binding energy per nucleon of nucleus is denoted by $E_bn$ and radius of nucleus is denoted as $r$. If mass number of nuclei $A, B$ and $64$ and $125$ respectively then

• A. $r_ {A} < r_ {B}, E_ {bnA} < E_ {bnB} $
• B. $r_ {A} < r_ {B}, E_ {bnA} < E_ {bnA} $
• C. $r_{A} = \frac {4}{5} r_{B}, E_ {bnA} < E_ {bnB}$
• D. $r_{A} < r_{B}, E_ {bnA} > E_ {bnB}$

Answer 1

Answer: (D)

$r$ increases with increasing $A$ mass number
So, $r_{A} < r_{B}$ as mass number of $A$ is smaller
$E_{b} n$ decreases with increasing A for $A > 56$,
${ }^{56} Fe$ has highest $E_{b n}$ value.
So, $E_{b n}$ for $A =64$ is larger as compared to $E_{b n}$ for nucleus with $A =125$
$E_{b n A}>E_{b n B}$