Transfer of Thermal Energy Flashcards
Principle of transfer of thermal energy
Thermal energy always flows from a region of higher temperature to a region of lower temperature. Net flow of thermal energy occurs only when there is a difference in temperature
What is conduction
Conduction is the transfer of thermal energy through a medium without any flow of the medium
How does conduction work
-Particles at the heated end vibrate vigorously
-They collide with neighbouring particles and transfer their energy
-Eventually the particles at the cooler end are also set into vigorous vibration
What is convection
Convection is the transfer of thermal energy by means of convection currents in a fluid, due to a difference in density
How does convection work
-Thermal energy is transferred through the actual movement of the heated particles from the warmer to cooler parts of the fluid
What is radiation
Radiation is the transfer of thermal energy in the form of electromagnetic waves such as infrared radiation without the aid of a medium
How does radiation work
-All bodies emit infrared radiation
-Infrared radiation does not require a medium to be transmitted. This is how the earth is warmed by the sun
-The rate of emission of radiation is affectred by a few factors
What affects radiation (skip to ans)
-Colour
-Shiny/dull
-Surface area
-Surface temperature
