efficiency and dissipation of energy Flashcards
What eventually happens to both useful and wasted energy
It is transferred to and warms the surroundings (dissipated)
When can friction be useful in a system
In the brakes for a vehicle such as a car
What happens to energy as it dissipates
It becomes less and less useful
What is input energy
The energy that is supplied to a device
How does one calculate efficiency
Useful energy out
————————— X 100
Total energy in
Give 3 ways in which energy is wasted
1) friction between moving parts
2) air resistance
3) electrical resistance
How can efficiency be increased
Reducing wasted energy
Give an example of reducing wasted energy regarding:
1) friction
2) air resistance
3) electrical resistance
1) Lubrication to reduce friction
2) Streamline vehicles to reduce air resistance
3) Copper wires to reduce electrical resistance
How does one calculate input energy
Useful energy out + wasted energy
Give an example of increasing efficiency regarding electrical
Some components in a circuit are more energy efficient such as LEDs in comparison to filament lamps
What is the correlation between thermal conductivity and energy transfer
Higher thermal conductivity = higher rate of energy transfer across material
