The mass of a nucleus is 0.042 amu less than the sum of the masses of 3 protons and 4 neutrons. the binding energy per nucleon in 7 3li is: 5.6 mev 10 mev 13 mev 39 mev

5.6 Mev

Explanation: Binding energy is calculated by using the formula,

bonding energy = mass defect x 931 Mev

mass defect is given as 0.042 amu.

So, binding energy = 0.042 x 931 Mev = 39.012 Mev

Sum of protons and neutrons is known as number of nucleons. Li has 3 protons and 4 neutrons.

So, number of nucleons = 3+4 = 7

Binding energy per nucleon =

binding energy per nucleon = 5.6 Mev

So, the binding energy per nucleon for Li is 5.6 Mev where Mev stands mega electron volt.