Energy Flashcards
BOOOOOOOOOOOOOOOO >:( (33 cards)
What is energy?
A physical quantity that can be stored by systems or objects
(in Joules (J))
What are the eight energy stores?
- kinetic
- gravitation potential
- elastic potential
- chemical potential
- nuclear potential
- electrostatic potential
- magnetic potential
- thermal potential
What are the four energy transfers?
- mechanical work
- by radiation (as a wave)
- by heating (bc of temp diff)
- electrical transfer
What is kinetic energy?
(KE)
Energy of movement. The more speed, the more KE.
What is gravitational potential energy?
(GPE)
Energy stored by an object raised to a height. The more height, the more GPE.
What is elastic potential energy?
(EPE)
Energy stored by stretching or compressing a material. The more extension/compression, the more EPE.
What is chemical energy?
Energy stored in the bonds creating a molecule. The stronger bonds, the more chemical energy.
What is nuclear energy?
Energy stored in the bonds between nucleons. The stronger bonds, the more nuclear energy
What is electrostatic energy?
Energy stored between two charged objects/particles. The more charge, the more electrostatic energy.
What is magnetic energy?
Energy stored between two magnetic objects/poles. The stronger magnets, the more magnetic energy.
What is thermal energy?
Energy due to temperature. The higher temperature, the more thermal energy
What is the law of conservation?
Energy cannot be created or destroyed, only transferred from one store to another
What is efficiency?
How much of the input energy comes out in a useful form
What is the formula for efficiency?
Efficiency = useful output/total output
How can thermal energy be transferred?
- conduction
- convection
- radiation
How does conduction work?
Particles gain kinetic energy near the heat source and the vibrations are passed to neighbouring atoms
Why are metals conductive?
There are free electrons which transfer the energy more quickly
Where does conduction occur?
In solids
What is convection?
What particles with more heat energy rise and particles with less heat energy take its place.
Where does convection occur?
In fluids (liquids and gases)
What is radiation?
in thermal energy
The emission of radiation from a object with a temperature higher than absolute zero
True or False:
All cold objects emit IR radiation
False
Only warm objects emit IR radiation
What factors effect IR radiation emission and absorption?
- surface colour
- surface area
- surface lustre
What type of surface are the best emitters of IR?
Dull black surfaces
