Binding Energy Per Nucleon

Binding Energy Per Nucleon

The Binding Energy per Nucleon is the average energy required to extract one nucleon from the nucleus.

Thus, binding energy per nucleon

Binding Energy Curve and its Features

Binding energy per nucleon as the average energy per nucleon needed to separate a nucleus into its individual nucleons.

Binding energy curve is a plot of the binding energy per nucleon versus the mass number for large nuclei.

The binding energy per nucleon as a function of mass number

The main features of his curve are give below:

(i) The binding energy per nucleon (E_bn) is practically constant, i.e. practically independent of the atomic number for nuclei of middle mass number (30 < A < 170). The curve has a maximum of about 8.75 MeV for A = 56 and has a value of 7.6 MeV for A = 238.

(ii) Binding energy per nucleon is lower for both light nuclei (A<30) and heavy nuclei (A>170).

From above two observations we can draw the conclusions given below:

(a) The force is attractive and sufficiently strong to produce a binding energy of a few MeV per nucleon.

(b) The constancy of the binding energy in the range 30 < A < 170 is a consequence of the fact that the nuclear force is short-ranged.

(c)A very heavy nucleus, say A = 240, has lower binding energy per nucleon compared to that of a nucleus with A = 120. Thus if a nucleus A = 240 breaks into two A = 120 nuclei, nucleons get more tightly bound. This implies energy would be released in the process.

(d) Consider two very light nuclei (A ≤ 10) joining to form a heavier nucleus. The binding energy per nucleon of the fused heavier nuclei is more than the binding energy per nucleon of the lighter nuclei. This means that the final system is more tightly bound than the initial system. Again energy would be released in such a process of fusion. This is the energy source of the sun.