Calculate the defect of helium nucleus

1 amu=1.67×10  

−27

kg

Using this and Einsteins relation, we get the energy equivalent to the rest mass as:

E=mc  

2

=(1.67×10  

−27

×0.0304)×(3×10  

8

)  

2

=4.569×10  

−12

J

Converting this energy in electron volts.

E=  

1.6×10  

−19

4.569×10  

−12

=28MeV

This is per nucleon of Helium. One Helium nucleus has four nucleons.

the answer is 75.0%.