01 Force and Motion II
02 Pressure
03 Electricity
04 Electromagnetism
05 Electronics
06 Nuclear Physics
07 Quantum Physics

7.1.2 Black Body

  1. A black body is an idealised physical body that absorbs and emits all electromagnetic waves (including light and heat) incident on it.
  2. A black body is a perfect absorber and also a perfect emitter of radiation.
  3. Classical physics cannot explain the black body emission, especially at high frequency.
    1. Classical wave theory explains light wave as a continuous spectrum.
    2. Energy of wave depends on its intensity.
    3. Energy emitted increases when wavelength becomes shorter.
    4. However, experimental results as shown in Diagram below show the energy peaking and then decreasing as the wavelength becomes shorter.