Heat Radiation Flashcards
What does heat energy do?
It tends to flow away from hotter objects to its cooler surroundings.
How many ways is heat transferred?
3 different ways.
Name the 3 ways heat energy is transferred.
Radiation.
Conduction.
Convection.
What is heat radiation?
The transfer of heat energy by infrared radiation.
What does conduction and convection involve?
The transfer of energy by particles.
What is conduction?
The main form of heat transfer in solids.
What is convection?
The main form of heat transfer in liquids and gases.
What can infrared radiation be emitted by?
Solids.
Liquids.
Gases.
What can any object do?
Emit or absorb infrared radiation, whether or not conduction or convection are also taking place.
The bigger the temperature difference between a body and its surroundings the what?
The faster energy is transferred by heating.
What are all objects continually doing?
Emitting and absorbing infrared radiation.
Where is infrared radiation emitted from?
The surface of an object.
What object emits more radiation than it absorbs?
An object which is hotter than its surroundings.
As it cools down.
What object absorbs more radiation than it emits?
An object which is cooler than its surroundings.
As it warms up.
The hotter an object is the…
More radiation it radiates in a given time.
When can you feel infrared radiation?
If you stand near something hot
Eg fire or touch the bonnet of a recently parked car.
What does radiation depend on?
Surface colour.
Texture.
What surfaces absorb infrared radiation?
Dark.
Matt.
What surfaces emit more infrared radiation?
Light.
Shiny.
Gloss white or silver.
Light. shiny surfaces do what?
Reflect a lot of infrared radiation falling on them.
Give an example of something which emits infrared radiation?
Vacuum flasks.
Silver inner surface to keep heat in or out depending on whether its storing hot or cold liquid.
What do solar hot water panels contain?
Water pipes uder a black surface.
Radiation from the sun does what?
Its absorbed by the black surface to heat the water in the pipes.
The water can be used for what?
Washing.
Pumped into radiators to heat buildings.
