The binding energies of deutron `(._1H^2)` and `alpha`-particle `(._2He^4)` are 1.25 and 7.2 MeV/nucleon respectively. Which nucleus is more stable? Calculate binding energy per nucleon of `._(26)Fe^(56). M(._(26)Fe^(56))`=55.934939 a.m.u, m(proton)=1.007825 a.m.u., m(neutron) =1.008665 a.m.u.