Energy Flashcards
What is a system?
An object or a group of objects.
What happens when a system changes?
There are changes in the way energy is stored (it is redistributed).
What does a Sankey diagram show?
How energy changes stores, one energy form redistributing into other forms.
What is internal energy?
The sum of all the kinetic and potential energy in the particles that make up a system.
What happens when work is done on a system?
It increases the energy stored in the system.
What might a temperature increase depend on?
The mass of the substance heated.
What the substance is.
The energy input.
What is the specific heat capacity of a substance?
The amount of energy required to raise the temperature of one kilogram of substance by one degree Celsius.
What is the Law of the Conservation of Energy?
Energy cannot be created or destroyed, only transferred from one store to another.
How is wasted energy caused?
Through unwanted energy transfers, typically heat.
How can unwanted energy transfers be reduced?
Lubrication (reduces the friction that produces heat).
Tightening loose parts (prevents unwanted vibration, which wastes energy as sound).
Thermal insulation (reduces heat loss).
What does the rate of cooling depend on in a system which is a building?
Thickness and thermal conductivity of walls.
What are some of the main uses of energy resources?
transport, electricity generation, heating
List some renewable energy resources.
biofuel, wind, water (hydroelectricity), geothermal, tidal, solar, water waves
List some non-renewable energy resources.
nuclear fuel, coal, oil, gas
What happens when energy is transferred?
It is stored or dissipated.
