An extended source in physics refers to an object or entity that emits or reflects radiation or particles over a relatively large area or volume, as opposed to a point source, which emits or reflects radiation from a single point.
Key points about extended sources:
Size and Area: Extended sources have dimensions that are not negligible compared to the distances involved in the observation or measurement. They can cover significant areas or volumes, emitting radiation or particles from multiple points within their extent.
Radiation Distribution: Unlike point sources, which emit radiation uniformly in all directions from a single location, extended sources emit radiation or particles from multiple locations across their surface or volume, leading to a more complex radiation distribution pattern.
Examples: Examples of extended sources include large celestial bodies like stars or galaxies emitting light across their surface, extended light sources such as fluorescent tubes or lamps, and isotropic radiation emitted from extended radioactive materials.
Observation and Analysis: The study and analysis of extended sources often involve considering the spatial distribution of emitted radiation, the flux or intensity of radiation across different areas, and understanding how the source’s size and shape impact its observed characteristics.
