Question

what is umbra and what is penumbra

Answer 1

Umbra, penumbra and antumbra of Earth and images that could be seen at some points in these areas (note: sizes and distances are not to scale

The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaqueobject. For a point source 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 of darkness, such as in sunspots.

Answer 2

The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object.