Nuclear Energy and Radioactive Decay

This lesson covers the origin of nuclear energy, the concept of mass-energy equivalence, nuclear waste management, and the debate around nuclear power — as required by the Edexcel GCSE Physics specification (1PH0), Topic 6: Radioactivity. You need to understand where the energy in nuclear reactions comes from, the challenges of nuclear waste disposal, and be able to evaluate the arguments for and against nuclear power.

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Where Does Nuclear Energy Come From?

The energy released in nuclear reactions (both fission and fusion) comes from a tiny amount of mass being converted into a large amount of energy.

Mass-Energy Equivalence (Awareness Level)

Albert Einstein showed that mass and energy are related by the equation:

E = mc²

Where:

• E = energy (joules, J)
• m = mass (kilograms, kg)
• c = speed of light (3 × 10⁸ m/s)

Because c² is an enormous number (9 × 10¹⁶), even a tiny amount of mass converts into a huge amount of energy.

How This Applies to Nuclear Reactions