Fresnel diffraction; geometrical shadow

AI Thread Summary
Geometric shadow refers to the area where light is obstructed by an object, resulting in a region where no direct light reaches. It is defined as the set of points where a line drawn from a light source to those points intersects an obstacle. This concept represents the shadow that would exist without the effects of diffraction. In essence, geometric shadows illustrate the basic principles of light obstruction in a straightforward manner. Understanding this concept is crucial for studying phenomena like Fresnel diffraction.
j-lee00
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What is geometrical shadow qualitatively? please don't refer me to hyper physics
 
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A geometric shadow is a set of points (or a region of space) where drawing a line between said points and a source always results in the line intersecting some obstacle.

A looser explanation would be that a geometric shadow is the shadow objects would possesses in the absence of diffraction.

Claude.
 
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