P6.3 - Black Body Radiation

• What do all black bodies (objects) emit and absorb?

  Infrared radiation
• What happens to the quantity of infrared radiation emitted by an object as temperature increases?

  The hotter the object, the more infrared it will emit.
• What is a perfect black body?


  An object that absorbs all of the radiation that is incident upon it
• How much radiation does a perfect black body reflect or transmit?


  None
• Why is a perfect black body the best possible emitter of radiation?

  It is a perfect absorber since it absorbs all radiation incident on it, and is also a perfect emitter.
• Other than the intensity of radiation emitted, how does increasing the temperature of an object affect its emissions?

  The wavelength distribution of any emission is dependent on the object's temperature.
• What can be said about the rates of emission and absorption for a body at constant temperature?

  The body is absorbing and emitting radiation at the same rate.
• What can be said about the rates of emission and absorption for a body increasing in temperature?

  The body is absorbing radiation faster than it is emitting it.
• Give 2 factors that affect the temperature of the Earth

  1. The Earth's rate of absorption and emission of radiation
  2. The amount of reflection of radiation into space.