Answers

2016-03-27T20:35:59+05:30
The umbra is the innermost and darkest part of a shadow
                                 whereas
The penumbra is the region in which only a portion of the light source is obscured by the occluding body.

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2016-03-27T20:40:20+05:30
UMBRA--------> The umbra is the area of the shadow where all the light from the source has been blocked, preventing any light from falling on the surface. ................... PENUMBRA----------> The penumbra, or partial shadow, is a section where light from only part of the source is blocked, resulting in an area where the light is dimmed, but not totally absent.
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