Q1. What is thermal law of radiation? Describe any two types of thermal laws of radiation in remote sensing.
- Thermal radiation is electromagnetic energy emitted by objects above 0 Kelvin due to their temperature.
- Stefan-Boltzmann Law: Total radiant exitance (M) is proportional to the fourth power of absolute temperature (T⁴).
- Formula for Stefan-Boltzmann Law: M = εσT⁴ (where ε is emissivity, σ is Stefan-Boltzmann constant).
- Wien's Displacement Law: Peak emission wavelength (λ_max) is inversely proportional to absolute temperature (T).
Answer: The thermal law of radiation describes the principles governing the emission of electromagnetic energy from objects due to their temperature. All objects with a temperature above absolute zero (0 Kelvin) continuously emit thermal radiation. This radiation is a form of electromagnetic energy, and its characteristics – such as total emitted power and the dominant wavelength of emission – are directly related to the object's absolute temperature. In remote sensing, understanding these laws is cru...