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Efficiency
A measure of how good a device is at transferring energy input to useful energy output
Total input energy
The total amount of energy supplied to a device
Useful energy output
The amount of energy that is transferred to useful energy stores
Wasted energy output
The amount of energy that is wasted or dissipated to the surroundings
Efficient device
A device that wastes very little of its input energy
Inefficient device
A device that wastes most of its input energy
Efficiency = useful output energy transfer ÷ total input energy transfer
The equation linking efficiency, useful output energy transfer and total input energy transfer
Efficiency = useful power output ÷ total power input
The equation linking efficiency, useful power output and total power input
Percentage efficiency
Found by multiplying the efficiency by 100
What is meant by an efficiency greater than 1 or 100%
More energy is being transferred than is being supplied
Why can't you have an efficiency greater than 1 or 100%
This would would break the law of conservation of energy as it would mean that energy is being created
Reasons devices waste energy
1) Friction between their moving parts
2) Heat due to electrical resistance
3) Unwanted sound or light
(higher-tier only)
How to improve efficiency
Reduce the amount of energy that a device wastes or dissipates to the surroundings
(higher-tier only)
Ways to improve efficiency
1) Lubricate mechanical devices to reduce the friction between moving parts of the machine
2) Insulate heating devices to reduce the dissipation of thermal energy to the surroundings
