Nuclear Fusion (AQA GCSE Physics)

• Small nuclei can react to release energy in a process called nuclear fusion
• Nuclear fusion is defined as:

When two light nuclei join to form a heavier nucleus

• This process requires extremely high temperatures to maintain
  • This is why nuclear fusion has proven very hard to reproduce on Earth

• Stars use nuclear fusion to produce energy
• In most stars, hydrogen atoms are fused together to form helium and produce lots of energy

Two hydrogen nuclei are fusing to form a helium nuclei

• The energy produced during nuclear fusion comes from a very small amount of the particle’s mass being converted into energy
• Albert Einstein described the mass-energy equivalence with his famous equation:

E = m × c²

• Where:
  • E = energy released from fusion in Joules (J)
  • m = mass converted into energy in kilograms (kg)
  • c = the speed of light in metres per second (m/s)

• The amount of energy released during nuclear fusion is huge:
  • The energy from 1 kg of hydrogen that undergoes fusion is equivalent to the energy from burning about 10 million kilograms of coal

ANSWER:  B

• • Hydrogen nuclei have positive charges
  • So two hydrogen nuclei would have a repulsive force between them
  • High temperatures are required to give the nuclei enough energy to overcome the repulsive force
  • The answer is not A because the products of the hydrogen fusion shown in the reaction is helium
    • Helium is an inert gas

  • The answer is not C because hydrogen is a very abundant element
    • It is the most common element in the universe

  • The answer is not D because hydrogen fusion would produce a huge amount of energy