Fission and fusion
Fission
Fission is a process in which a nucleus with a large mass number splits into two nuclei, which have smaller mass numbers.
You need to know:
- Neutrons are usually released when fission takes place.
- Fission of a nucleus may be spontaneous, that is, it may happen at random due to internal processes within the nucleus.
- Fission can also be induced by bombarding a nucleus with a neutron. Induced fission is used to generate nuclear power and for weapons.
- The products formed during fission gain kinetic energy. It is this energy that is harnessed in nuclear power stations.
Fusion
Fusion is a process in which two nuclei combine to form a nucleus of larger mass number.
- Fusion is the main nuclear process that occurs in the Sun and other stars.
- The products of fusion reactions also gain kinetic energy that can be harnessed.
Albert Einstein in his famous equation \(E = mc^{2}\) showed that mass and energy are equivalent.
In this equation:
- \(E\) is energy in joules
- \(m\) is mass in kilograms
- \(c\) is the speed of light \(3 \times 10^{8}ms^{-1}\)
Question
If we were to completely convert 1 kg of oil into energy, how much energy would we obtain?
\(E = mc^{2}\)
\(=1 \times (3 \times 10^{8})^{2}\)
\(= 9 \times 10^{16}J\)
Of course when we burn oil we do not convert all of its mass into energy. Most of the mass remains so we only get a minute fraction of this quantity of energy by burning fuel.
