This type of surface is a good absorber and emitter of thermal radiation - ✔✔✔Dark, rough (matt)
surface
This type of surface is a bad absorber and emitter of thermal radiation - ✔✔✔Light, shiny surface
In this process particles vibrate colliding with each other passing energy along. Solids are best at it, then
liquids, then gases. - ✔✔✔Conduction
In this process particles move around carrying energy with them. Gases are best at it, then liquids then
solids - ✔✔✔Convection
This process doesn't require a medium (substance) to transfer energy. The energy is carried in the form
of waves - ✔✔✔Radiation
Factors affecting the rate of heat transfer - ✔✔✔1. Temperature difference to the surroundings
2. Surface area
3. Nature of surface (e.g shiny/matt)
The total energy supplied to a device or an appliance. It is often electrical - ✔✔✔Total Input Energy
Energy converted by a device into the form(s) the device was designed for. - ✔✔✔Useful energy
Energy converted by a device into the form(s) the device was NOT designed for. - ✔✔✔Wasted energy
, Useful energy transferred by the device divided by total energy input to the device - ✔✔✔Efficiency
Energy cannot be created or destroyed only transformed into other forms - ✔✔✔The principle of
conservation of energy
Where does all energy end up eventually? - ✔✔✔It is transferred to the surroundings, warming them
in the process.
The unit of energy used in electricity bills - ✔✔✔kilowatt-hour (kWh)
What are the useful and wasted energies transformed by a radio? - ✔✔✔USEFUL: Sound
WASTED: Heat
What are the useful and wasted energies transformed by a TV? - ✔✔✔USEFUL: Sound, Light
WASTED: Heat
What are the useful and wasted energies transformed by a hairdryer? - ✔✔✔USEFUL: Heat, Kinetic
WASTED: Sound
What are the useful and wasted energies transformed by a car? - ✔✔✔USEFUL: Kinetic
WASTED: Heat, Sound
The unit of energy normally used (expect in electricity bills) - ✔✔✔joules (J)
Absorption - ✔✔✔When a wave hits an object and is absorbed the energy of the wave can heat up the
object