Final answer:
Two H-2 atoms fusing to He-4 release more energy than two Li-6 atoms fusing to C-12, as lighter elements like Hydrogen converted to Helium release more energy due to higher binding energy per nucleon up to iron on the curve.
Step-by-step explanation:
Energy Release in Fusion Reactions
When comparing two fusion reactions, two H-2 atoms fusing to He-4 releases more energy than two Li-6 atoms fusing to C-12. This is because the fusion of lighter elements, such as hydrogen isotopes, into Helium involves a greater conversion of mass to energy according to the mass-energy equivalence principle of E=mc^2. The energy released in such fusion reactions is largely due to the difference in binding energy per nucleon, which is greater in lighter elements up to iron on the binding energy curve.
The binding energy per nucleon is at its peak in iron, meaning that fusion reactions involving elements lighter than iron (such as Hydrogen and Helium) release energy, while fusing elements heavier than iron (like Lithium to Carbon) requires an input of energy. The considerable energy release in fusing two Hydrogen nuclei (such as Deuterium, H-2) into Helium is what powers our Sun and other stars, making it a potential source for clean and powerful energy generation here on Earth.