Energy and Efficiency Flashcards
what happens to wasted energy from a device
it warms up the surroundings
why is wasted energy less useful
it becomes increasingly spread out
2 factors affecting the amount of energy a device transfers
- the power
- how long the device is on for
name the diagram used to determine the efficiency of a device
a sankey diagram
useful energy transfer occurring in a lawn mower
electrical energy to kinetic energy
what is payback time
the amount of time taken before the energy saved by a device= the amount of money spent on the device
how can a device be made more efficient
some of the wasted energy is used for useful purposes eg. wasted heat energy in a power station is used to heat homes
3 reasons why LED bulbs should be used over Filament bulbs
- it will save money
- they last a lot longer
- they use less energy and so reduce carbon emissions
what does efficiency mean
how much useful energy is transferred as a proportion of the amount of energy given overall
a Hoover has a power of 2kw. What does this tell us
2000j of energy are transferred every second
