Question

explain why nuclear fission and nuclear fusion release large amounts of energy.

Explanation:

• Nuclear fission: When a heavy nucleus (e.g., \(U - 235\)) splits, the mass of the products is less than the mass of the reactants. According to Einstein's mass - energy equivalence formula \(E=mc^{2}\), the lost mass (\(\Delta m\)) is converted into energy (\(E=\Delta mc^{2}\)). Since \(c = 3\times10^{8}\space m/s\) (a very large number), even a small amount of mass loss results in a large amount of energy.
• Nuclear fusion: When light nuclei (e.g., hydrogen isotopes \(^{2}_{1}H\) and \(^{3}_{1}H\)) combine, the mass of the resulting nucleus is less than the sum of the masses of the original nuclei. Again, using \(E = mc^{2}\), the mass difference is converted into a large quantity of energy. The strong nuclear force is involved in binding the nuclei, and when the nuclei re - arrange (either by splitting in fission or combining in fusion), the energy associated with the nuclear binding energy is released.

Answer:

Nuclear fission and fusion release large amounts of energy because of mass - energy equivalence (\(E = mc^{2}\)). In fission, a heavy nucleus splits, and the mass of products is less than reactants. In fusion, light nuclei combine, and the mass of the product is less than the sum of reactant masses. The “lost” mass is converted into energy, and since \(c\) (speed of light) is very large (\(c=3\times 10^{8}\space m/s\)), even a small mass loss (\(\Delta m\)) leads to a large energy release (\(E=\Delta mc^{2}\)).