Question

Energy is released in both nuclear fission and fusion because:

• A. The total mass before and after the reaction remains the same.
• B. The mass of the products is less than the mass of the reactants.
• C. Energy is not related to mass change.
• D. Both reactions involve a change in atomic number.

Answer 1

The Correct Option is B

Energy is released in both nuclear fission and fusion due to a significant principle known as mass-energy equivalence, articulated by Albert Einstein's famous equation: \(E=mc^2\). This equation implies that a small amount of mass can be converted into a large amount of energy since \(c\) (the speed of light) is a significant number (\(3 \times 10^8\) meters per second).

In both nuclear fission and fusion reactions, the key reason for energy release is the mass defect. This is the difference in mass between the reactants and the products:

1. In nuclear fission, a heavy nucleus splits into smaller nuclei, and the combined mass of these smaller nuclei is less than the original nucleus.
2. In nuclear fusion, light nuclei combine to form a heavier nucleus, and again, the mass of the resulting nucleus is less than the sum of the masses of the original nuclei.

In both cases, the "missing" mass (known as the mass defect) is converted into energy. The correct answer to the question arises because:

The mass of the products is less than the mass of the reactants.

This reduction in mass results in the release of energy according to the formula, \(E=mc^2\).