Question

An example of nuclear fusion reaction is:
A. ${}_{90}^{233}Th + {}_0^1n \to {}_{90}^{234}Th$
B. ${}_{13}^{27}Al + {}_2^4He \to {}_{15}^{30}P + {}_0^1n$
C. ${}_2^3He + {}_2^3He \to {}_2^4He + 2{}_1^1H$
D. ${}_{92}^{239}U \to {}_{93}^{239}Np + {}_{ - 1}^0e$

Answer 1

Hint: We know that the process of combining two lighter nuclei to form a heavy nucleus is called nuclear fusion, but not the bombardment of the particles. It requires a very high temperature to fuse.

Complete step by step answer:
Because, the process of combining two light nuclei to form a heavy nucleus with the release of a large amount of energy is known as nuclear fusion. In option (A) thorium is bombarded with neutron, in option (B) also Aluminum is bombarded with alpha particles and in Option (D) uranium decays but in option (C) two lighter nuclei combine to form a heavier nucleus called fusion. This given fusion reaction takes place in the proton-proton cycle in stars.
When two light nuclei are made to combine to form a heavy nucleus a large amount of energy is released is called nuclear fusion.
When two light nuclei are combining to form a heavy nucleus, the mass of the product nucleus is slightly less than the sum of the masses of the light nuclei fusing together. As a result in nuclear fusion there is a mass difference. Because of this mass difference there is a release of a very large amount of energy according to the relation $E = \Delta m{c^2}$ .
Hence the correct answer is (C).
Example: when two nuclei of heavy hydrogen ($H_1^2$ ) are combined,
${H^2} + H_1^2 \to H_1^3 + H_1^1 + 4.0{\text{MeV}}$
The nucleus of tritium $H_1^3$ so formed can again fuse with the deuterium nucleus,
$H_1^3 + H_1^2 \to He_2^4 + n_0^1 + 17.6MeV$
Energy released per fusion is less than the energy released per fission. The energy released per unit mass in nuclear fusion is greater than the energy released per unit mass in nuclear fission. The final products in nuclear fusion are not radioactive.
The nuclear reaction is done by raising the temperature of the substance so that nuclei have enough kinetic energy to fuse is called thermonuclear fusion. The energy obtained from the sun and star is called stellar energy.

Note:
Nuclear fusion cannot be controlled.
Fusion reaction takes place only at high temperature.
Energy released per unit mass of the reactant is large.