Physics Term 1 Test/Revision Year 11

Heat

The thermal energy transfer between a hotter object to a cooler object until thermal equilibrium has been reached

Temperature

The measure of the average kinetic energy of the particles in the object. Measured in degrees Celsius or Kelvin

Thermal Energy

the total of potential and kinetic energies of all particles in an object

Thermal Equilibrium

when two objects have the same temperature and heat transfer between objects stops

Conduction

Process by which heat is transferred from one object to another without the net movement of particles (atoms or molecules). Occurs within materials that are in thermal contact

Factors Affecting Thermal Conduction

• nature of the material: larger a material’s thermal conductivity, more rapidly it will conduct heat energy

• temperature diff between two objects: greater this is, faster rate of energy transfer

• thickness of the material: thicker materials require more collisions

• surface area: increasing surface area increases rate of conduction

Convection

• transfer of thermal energy withiin a fluid (liquid or gas)

• involves the mass movement of particles

Radiation

• transfer of heat without the movement of matter

Factors affecting rate of emission and absorption (radiation)

• Surface area: larger this is, higher rate of radiant transfer

• Temperature: greater diff temp means greater rate of transfer

• wavelength of incident radiation: matte black surfaces are almost perfect absorbers of radiant energy. Highly reflective surfaces are good reflectors of all wavelengths.