AQA GCSE triple higher physics topic one - energy

Energy stores

Chemical, kinetic, thermal, gravitational potential, elastic potential, magnetic, electrostatic and nuclear.

Energy transfer

Energy moves between stores through heating, radiation, electrical work or mechanical work.

Conservation of energy

Energy cannot be created or destroyed; it is transferred between stores.

Kinetic energy

Ek = ½mv².

Gravitational potential energy

Ep = mgh.

Elastic potential energy

Ee = ½ke², within the elastic limit.

Work done

Work done = force × distance moved in the direction of the force.

Power

Power = energy transferred ÷ time.

Efficiency

Useful energy output ÷ total energy input.

Percentage efficiency

Efficiency × 100%.

Wasted energy

Energy transferred to unwanted stores, often through heating or sound.

Conduction

Energy transfer through a material by particle collisions and, in metals, free electrons.

Convection

Energy transfer by the movement of warmer and cooler fluids.

Radiation

Energy transfer by electromagnetic waves, including infrared.

Insulation

Reduces unwanted energy transfer, often by trapping air or using low

Specific heat capacity

Energy required to raise the temperature of 1 kg of a substance by 1°C.

Specific heat capacity equation

ΔE = mcΔθ.

Specific latent heat

Energy required to change the state of 1 kg of a substance without changing its temperature.

Specific latent heat equation

E = mL.

Change of state

Energy changes particle potential energy during melting or boiling without changing temperature.

Renewable energy

Energy from resources replenished naturally, such as wind, solar, hydroelectric and tidal.

Non

renewable energy

Fossil fuels

Burning coal, oil and gas releases energy and carbon dioxide, with other pollutants possible.

Nuclear fission

Splitting a large unstable nucleus to release energy and neutrons.