Temperature and Energy Flashcards
What is temperature a measure of?
How much Energy of motion (kinetic energy) the molecules of a material possess
What is the normal temperature scale?
Degrees Celcius
What do hot bodies radiate?
A characteristic spread of electromagnetic energy know as blackbody radiation.
If all bodies radiate electromagnetic energy what counts?
The difference between radiation received and radiation emitted.
What is a Blackbody?
One that absorbs completely any radiation that falls on it.
Why are bodies coloured?
They don’t absorb all the radiation that falls on them.
what does the total radiant energy emitted per m^2 of surface per second depend on, and what law is it??
A blackbody’s absolute temperature and the Stefan-Boltzmann law.
What does Earth’s average emissivity depend on?
The surface cover
What is inversely proportional to the maximum amount of radiation at a wavelength that a hot body emits and what law is this?
Their average temperature and is Wein’s law.
What does a hot sun emit most of its radiation as and what is it transmitted by?
Emits most of it’s radiation as short-wave radiation and is transmitted by the atmosphere
What is Far infrared, longer wavelengths known as?
Long-wave radiation
Explain the Radiation balance between the Earth and the Sun.
The Earth receives the Sun’s energy from one direction and radiates it back into space in all directions.
What is the difference between the radiative equilibrium temperature and the average temperature on Earth caused by?
The atmospheric greenhouse effect
What is the Greenhouse Effect caused by?
The absorption of escaping wave radiation by H2O,CO2,N2O,O3 and CFCs and re-radiating it back to the surface.
What do the Greenhouse gases do?
They make the atmosphere almost opaque to long-wave radiation and effectively screen the Earth’s surface from the cold of space, raising the temperature.
