Unit 3 & 8 Flashcards
Temperature
a measure of the average random kinetic energy of the particles in a substance.
Specific Latent Heat of Fusion/Vaporization
the energy required to change the phase of 1kg of a substance from a solid/liquid to a liquid/gas without any temperature change.
Specific Heat Capacity
the energy required to heat 1kg of a substance by 1K.
Internal Energy
the total of the potential energy and the random kinetic energy of all the particles in the substance.
Absolute temperature
a temperature measured from absolute zero in kelvins.
Ideal Gas
a hypothetical gas whose molecules occupy negligible space and have no interactions, and which consequently obeys the gas laws exactly.
Boyle’s Law
for a fixed mass of gas at constant temperature the pressure is inversely proportional to the volume.
Charles’ Law
for a fixed mass of gas at constant pressure the volume is directly proportional to the absolute temperature.
Pressure Law
for a gas of fixed mass and volume, the pressure is directly proportional to the absolute temperature.
Mole
the number of molecules in 12g of carbon 12.
Molar Mass
the mass of a substance divided by the number of molecules.
Thermal Energy
the net amount of energy transferred between two bodies at different temperatures.
Pressure
force per unit area
Specific Energy
The energy released per unit mass of a fuel.
Energy Density
The energy released per unit volume of a fuel.
Primary Energy Source
a source of energy that has not been transformed or converted before use by the consumer.
uranium 235, crude oil, coal, sun, water, wind etc.
Secondary Energy Source
an energy source created using a primary source eg electricity.
Renewable Energy
energy generated from renewable resources, which are naturally replenished on a human timescale.
sunlight, wind, rain, tides, waves, and geothermal heat.
Conduction
the transfer of heat by collisions of particles and movement of electrons within a body
Convection
the movement of groups of atoms or molecules within fluids that arises through variations in density.
Thermal Radiation
The transfer of energy by means of electromagnetic radiation.
Black body
A hypothetical body that absorbs and emits all radiation that falls on it.
Intensity
Power emitted per square meter.
Albedo
The ratio of scattered radiation from the surface to incident radiation upon it.
Solar Constant
The mean solar intensity of EM radiation that would be incident on a plane perpendicular to the rays, at a distance of one AU from the Sun. SC = 1400 Wm^-2
Degradation of Energy
In any natural process, some energy becomes unavailable to do useful work.
Wien’s Displacement Law
The black body radiation curve for different temperatures peaks at a wavelength inversely proportional to the temperature
Stefan-Boltzmann Law
The radiated power from a black-body radiator is directly proportional to the fourth power of the black body’s surface temperature.
Emissivity
The ratio of energy/power emitted (per unit area) of a body to the energy/power emitted (per unit area) of a black body of the same dimensions and the same temperature.
