Question

Differentiate between nuclear fission and nuclear fusion. Give one example for each with nuclear reaction.

Hint:

To remember the distinction: "Fission" sounds like "fissure" (a split or crack), meaning breaking apart. "Fusion" means "fusing" things together into a single whole. Both processes release energy because the final products have a higher binding energy per nucleon than the initial reactants.

Answer 1

Concept: Nuclear transformations release energy by shifting nuclei toward a higher binding energy per nucleon. This can happen in two distinct ways depending on the mass numbers involved: splitting heavy elements (fission) or joining light elements (fusion).

Step 1: Comparative Tabulation.
[h!] {|l|p{6cm}|p{6cm}|} Parameter & Nuclear Fission & Nuclear Fusion
Definition & The process in which a heavy, unstable nucleus splits into two or more smaller, stable daughter nuclei. & The process where two or more lighter, fast-moving nuclei combine together to form a single heavier nucleus.
Starting Material & Requires heavy elements with large mass numbers (e.g., Uranium, Plutonium). & Requires light elements with small mass numbers (e.g., Hydrogen, Deuterium, Tritium).
Temperature & Can occur at normal ambient temperatures when triggered by thermal neutrons. & Requires extremely high temperatures (\(\sim 10^7 \text{ K}\)) to overcome electrostatic repulsion.

Step 2: Formulating Nuclear Equations.
Example of Nuclear Fission: When a heavy Uranium-235 nucleus absorbs a slow moving thermal neutron, it splits into Barium and Krypton along with three fast neutrons and a massive release of energy: \[ {}_{92}^{235}\text{U} + {}_{0}^{1}\text{n} \longrightarrow {}_{56}^{144}\text{Ba} + {}_{36}^{89}\text{Kr} + 3_{0}^{1}\text{n} + \text{Energy} \] Example of Nuclear Fusion: Under high temperature conditions, two small Deuterium isotopes fuse together to form a Helium-3 nucleus, releasing a neutron and energy: \[ {}_{1}^{2}\text{H} + {}_{1}^{2}\text{H} \longrightarrow {}_{2}^{3}\text{He} + {}_{0}^{1}\text{n} + 3.27 \text{ MeV Energy} \]