What is Umbra, Penumbra and Antumbra?
Answers
Answer:
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. Assuming no diffraction, for a collimated beam (such as a point source) of light, only the umbra is cast.
These names are most often used for the shadows cast by celestial bodies, though they are sometimes used to describe levels, such as in sunspots.
The umbra (Latin for "shadow") is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body.
The penumbra (from the Latin paene "almost, nearly") is the region in which only a portion of the light source is obscured by the occluding body.
The antumbra (from Latin ante, "before") is the region from which the occluding body appears entirely within the disc of the light source.
Answer:
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. ... These names are most often used for the shadows cast by celestial bodies, though they are sometimes used to describe levels, such as in sunspots.