Physics Exam — Kinetic, Potential, Renewable Energy and Efficiency
Study the types of energy (kinetic, potential, thermal, light, chemical, nuclear), the conservation principle, energy transformations in power stations, the differences between renewable and non-renewable sources, machine efficiency and electrical power.
Physics & Chemistry · Primary & Secondary
Energy is never created or destroyed — only transformed. When a car brakes, kinetic energy becomes heat. Electric car regenerative brakes convert it back to electricity.
Renewable: solar, wind, hydroelectric, geothermal, tidal (replenish naturally). Non-renewable: coal, oil, natural gas, uranium (finite, mostly emit CO₂). Spain already gets over 10% of its electricity from solar.
η = (useful energy / total energy) × 100%. LED bulb ≈ 90%. Combustion engine ≈ 30%. Solar panel ≈ 20%. Improving efficiency means less fuel and fewer emissions for the same output.
"A Year 7 student traces the chain coal plant → chemical → thermal → mechanical → electrical. The exam makes the abstract transformation visible step by step."
Tricks and techniques to master this topic faster:
Memorise the chain for a coal plant: chemical → thermal (steam) → mechanical (turbine) → electrical (generator).
Kinetic energy grows with the SQUARE of speed: doubling speed quadruples kinetic energy.
Power unit: Watt (W) = Joule per second. 1 kWh = 3.6 MJ (the unit on your electricity bill).
Nuclear energy is not renewable (uranium runs out) but is low-carbon during operation.
If you are studying Energy: Types, Transformations and Renewables, these curriculum topics complement each other:
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