Q. BE/nucleon relation with mass number
Haryana PMTHaryana PMT 2007
Solution:
The binding energy per nucleon for light nuclei is very small.
The variation of average binding energy per nucleon with mass number $A$ is shown in figure.
Average binding energy per nucleon for light nuclei like
${ }_{1} H^{1},{ }_{1} H^{2},{ }_{1} H^{3}$ is small.
For mass numbers ranging from $2$ to $20$, there are sharply defined peaks corresponding to ${ }_{2} He ^{4},{ }_{6} C ^{12},{ }_{8} O ^{16}$ etc.
The binding energy curve has a broad maximum in the range $A=30$ to $A=120$ corresponding to average binding energy per nucleon $=8.5 \,MeV$.
The peak value of the maximum is $8.8\, MeV /$ nucleon for ${ }_{26} Fe ^{56}$.
As the mass number increases, the binding energy per nucleon decreases gradually falling to about, $7.6 \,MeV$ per nucleon for ${ }_{92} U ^{238}$.
