(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?
(a) The process in which two nuclei of light elements (like that of hydrogen) combine to form a heavy nucleus (like that of helium), is called nuclear fusion.
When deuterium atoms are heated to an extremely high temperature under extremely high pressure, then two deuterium nuclei combine together to form a heavy nucleus of helium, and a neutron is emitted. A tremendous amount of energy is liberated in the process.
\(_{1}^{2}H + _{1}^{2}H \overset{Fission}\rightarrow\) \(_{2}^{3}He + _{0}^{1}n \) + tremendous amount of energy
(b) Because very high energy is required to force the lighter nuclei (which repel each other) to fuse together to form a bigger nuclei.