GCSE Physics · AQA 8463 · Topic 4.1

Energy

Key points

Energy is never created or destroyed: it is only transferred between stores (kinetic, gravitational potential, elastic potential, thermal, chemical, magnetic, electrostatic, nuclear).
Energy is transferred by heating, by forces doing work and by electric currents.
Key equations: $E_k = \frac{1}{2}mv^2$ , $E_p = mgh$ , $E_e = \frac{1}{2}ke^2$ , $\Delta E = mc\Delta\theta$ , $P = \frac{E}{t}$ and $P = \frac{W}{t}$ .
Energy that is not usefully transferred is usually dissipated to the surroundings as thermal energy, so it is wasted.
Efficiency = useful output energy ÷ total input energy (or the same with power). It is never more than 1 (100%).
Energy resources are renewable (wind, solar, hydro, tides, waves, geothermal, bio-fuel) or non-renewable (coal, oil, gas, nuclear). Each has advantages and disadvantages for reliability, cost and the environment.

Topic notesPremium

Energy is the thread that runs through the whole of GCSE Physics. This topic gives you the language of energy stores and transfers, the equations you will use in almost every other topic, and the big question of how we supply the energy…

Unlock the full notes with Premium

Premium includes full topic notes, the paper generator, self-quizzes and progress tracking.

See Premium plans Already Premium? Sign in

Sub-topics

Practise this topicPremium

Premium members can generate an exam-style paper with a mark scheme, or take a quick quiz, on Energy.

Back to all Physics topics