What is Blackbody Radiator? – Features and Laws | New Note [2024]

In this note, we are going to learn a topic called “What is Blackbody Radiator?“, and its features. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

What is Blackbody Radiator?

A blackbody radiator, also known as a blackbody, is an idealized physical entity that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The blackbody re-emits this energy flawlessly, making it a perfect emitter as well.

Some Features of Blackbody Radiator

Here we have listed some key features of this radiator –

• Perfect Absorber: It absorbs all incoming radiation without reflecting any, giving it a black appearance when cold.
• Perfect Emitter: It emits radiation uniformly in all directions and at all wavelengths, depending solely on temperature.
• Emission Spectrum: Planck’s law describes the radiation emitted by a blackbody, which has a defined spectrum that depends solely on temperature. As the temperature rises, the peak wavelength of emitted radiation moves to shorter wavelengths (Wien’s displacement equation), but total energy emitted rises (Stefan-Boltzmann relationship).
• Planck’s Law: This law describes the dispersion of electromagnetic radiation from a blackbody as a function of wavelength at a particular temperature.
• Wien’s Displacement Law: According to this equation, the wavelength at which the maximum emission of a blackbody spectrum occurs is inversely proportionate to the temperature.
• Stefan-Boltzmann Law: According to this law, the total energy radiated per unit surface area by a blackbody is proportional to the fourth power of its absolute temperature.