Question

(a) What is nuclear fusion? Explain with an example. Write the equation of the reaction involved.
(b) Why are very high temperatures required for fusion to occur?

Answer 1

(a) Nuclear fusion
Nuclear fusion is the process by which two nuclei of light elements combine to form a heavy nucleus.

Example:
When deuterium atoms are heated to an extremely high temperature under extremely high pressure, two deuterium nuclei combine to form a heavy nucleus of helium, and a neutron is emitted. A tremendous amount of energy is liberated in this fusion reaction.

Reaction:
${}_1{}^2\mathrm{H}+{}_1{}^2\mathrm{H}\to {}_2{}^3\mathrm{H}+{}_0{}^1\mathrm{n}+\mathrm{Tremendous}\mathrm{amount}\mathrm{of}\mathrm{energy}$

(b) When two positively charged nuclei are brought together, they repel each other. Therefore, a very high temperature is required to force the lighter nuclei to fuse together to form a bigger nucleus.