Physics - Energy Flashcards
Energy
Ability to do work
It can be stored
Potential energy
Energy that is stored and when released is converted to other forms of energy
All substances and objects possess potential energy
Gravitational potential energy
the energy that is stored by an object due to its height or position above the earth’s surface
Elastic potential energy
the energy that is stored by an object that is stretched
Chemical potential energy
the energy stored in chemical that when reacted together release heat, light or sound
Nuclear potential energy
energy stored in the nucleus of atoms that can release energy slowly, such as in a nuclear reactor, or quickly, such as in a nuclear explosion
Electrical potential energy
Energy that is carried by an electrical current (the movement of electrons, the negatively charged particles of atoms)
Kinetic energy
energy possessed by objects that are moving
Heat energy
energy that causes objects to get hotter
Light energy
Energy that makes light visible to the human eye
It may be released when an object gets hot or when a chemical reaction occurs
Mechanical energy definition and equation
The total energy an object has because of its motion (speed) and position
Potential energy + Kinetic energy
Is all energy converted useful energy?
most energy is usually converted into useful energy but some is converted into forms of energy that are wasted or not so useful
Law of Conservation of energy
energy can neither be created nor destroyed, only converted (changes forms)
Energy Efficiency
the amount of energy that is utilised as useful energy versus wasted energy
Why does higher temperature increase thermal (heat) energy?
this is as a higher temperature results to particles in an atom to move faster/quicker
The 3 ways of heat transfer
Conduction
Convection
Radiation
Conduction - Heat transfer
transfer of heat from the hotter end of a solid to the cooler end of a solid through the collision of neighbouring particles
Why is conduction easier among solids and liquids?
this is as the particles are closer together already in liquids and solids so the particles only need to move a small distance in order to collide with each other and transfer heat
Convection - Heat transfer
the movement of heat in liquids and gases usually through currents
A current is created when the warmer
(less dense) material rises forcing the
cooler (more dense) material to sink
Radiation - Heat transfer
Heat from the sun reaches Earth by electromagnetic waves (radiation)
Why is radiation different to conduction and convection?
unlike Conduction and Convection,
radiation can occur in empty space, as well as in solids, liquids, and gases
Conductors
Good conductors of heat
They heat up quickly when exposed to a source of thermal energy
Insulators
Poor conductors of heat
Insulators do not heat up
They keep cold things cold and hot things hot
Why are Insulators useful?
Insulators are useful as they can be used to slow the change of temperature, which means that warm or hot substances will stay hotter longer, while cold substances will also stay colder for longer
Heat transfer
the movement of heat from an object with a higher temperature to an object with a lower temperature
