Energy Flashcards
Energy can be stored as:
Kinetic Magnetic Thermal Electrostatic Elastic (potential) Gravitational (potential) Chemical (potential)
Energy can transfer from one store to another:
Electrically
Light
Sound
Mechanically
What are useful transfers
Intended transfers
What are wasted transfers
Unintended transfers
What is energy measured in
J (joules)
What’s does the law of conservation of energy state?
Energy cannot be created nor destroyed, but can only be turned into other forms
What are sankey diagrams?
A representation of energy transfers using arrow thickness to show amounts of energy. Draw to scale with labels
What is efficiency
A measure of how usefully a device transfers energy
Efficiency formula
Efficiency = useful energy out / total energy in
Unit for efficiency
Unitless
Or
% (x100)
How to measure electrical energy
Current x voltage x time = electrical energy
How to measure heat energy?
Volume x 4.2 x temp rise = heat energy
How to measure heat loss?
Electrical energy - heat energy = heat loss
