Question

Which of the following statements best describes nuclear fusion reaction?
A.) Two smaller nuclei are combined into a more massive nuclei
B.) The electrons are exchanged from one or more substances to produce a different substance, and the elements are the same in the products and reactants
C.) The nucleus of a large atom is split into two or more fragments
D.) The particles in the nucleus are changed, and one element is transformed into another element when particles in the nucleus are gained or lost
E.) Radiation is made

Answer 1

Hint: Nuclear fusion is a nuclear reaction which involves the fusion of lighter nuclei into heavier nuclei. The word fusion means combination or joining. In this process a large amount of energy is released due to the difference in total mass of the nuclei on the reactant and product side.

Complete step by step answer:
Nuclear fusion is a kind of nuclear reaction in which two lighter nuclei combine under suitable conditions to form heavier nuclei under suitable conditions. A lot of energy is released in this process.

The energy change in this process is due to a change in binding energy of the nuclei on the reactant and product sides. Binding energy is a measure of how tightly a nucleus is packed with protons and neutrons. The more the binding energy, the more tightly the nucleus is packed and more is its stability.

The heavier nuclei are more tightly bound than the lighter nuclei. Hence, the heavier nuclei have greater binding energy than the lighter nuclei. This difference in binding energy is released during the nuclear fusion process.
Hence, the correct option is A) Two smaller nuclei are combined into more massive nuclei

Note: Students might get confused between nuclear fission and nuclear fusion and may thus mark option C) as the correct answer. However, the two are essentially the opposites of each other. An easy way to remember the difference between nuclear fusion and nuclear fission is to understand the meaning of the words fusion and fission.
The word fusion means joining or combination (thus, nuclear fusion is the joining of lighter nuclei into heavier nuclei) and the word fission means fragmentation or breaking up (thus, nuclear fission is the fragmentation of a heavier nucleus into lighter ones).