blackbody radiation

• Black body


  A perfect absorber and emitter of radiation
• When a light bulb filament is heated, it emits a range of wavelengths that appear as different colors
• Electromagnetic spectrum


  • Infrared
  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Violet
• As temperature increases


  The emitted wavelengths shift towards shorter wavelengths (higher frequencies)
• Any material that absorbs energy will emit that energy as electromagnetic radiation until it reaches the same temperature as its surroundings
• Radiative cooling


  The process where a body emits electromagnetic radiation until it reaches the same temperature as its surroundings
• Black body radiation curve

  A graph showing the relationship between the intensity and wavelength of radiation emitted by a black body at different temperatures
• The peak wavelength of the black body radiation curve is inversely proportional to the temperature (Wien's law)
• Ideal black bodies do not exist, but good approximations include stars, the sun, and the inside of an oven
• The classical physics models could not explain the shape of the black body radiation curve, leading to the "ultraviolet catastrophe"
• Quantization of energy


  The idea that energy can only be absorbed or emitted in discrete amounts (quanta), not continuously
• Max Planck proposed the idea of energy quantization to resolve the black body radiation problem, leading to the formula that accurately described the experimental data
• Planck's solution was a mathematical fix, and the theoretical interpretation of energy quantization had to be further developed, which was later done by Albert Einstein
• Black body


  To stay in thermal equilibrium, a black body must emit radiation at the same rate as it absorbs, so it must also be a good emitter of radiation, emitting electromagnetic waves of as many frequencies as it can absorb, i.e. all the frequencies
• Blackbody radiation


  The radiation emitted by the blackbody
• Blackbody radiation


  The characteristics of blackbody radiation
• Laws explaining the characteristics of blackbody radiation

  • Wien's displacement law
  • Planck's law
  • Stefan-Boltzmann law
• Wien's Law


  is the flashcard for the concept: <front>Wien's Law</front> .back>A scientific principle stating that the peak wavelength of black body radiation is inversely proportional to temperature
• Frequencies


  The number of oscillations or cycles of a wave per unit time, measured in Hertz (Hz)
• Wavelengths


  The distance between two consecutive peaks or troughs of a wave, typically measured in meters (m) or nanometers (nm)
• Black Body Radiation


  A black body must emit radiation at all possible frequencies, from zero to infinity, and all possible wavelengths, from longest to shortest