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