Lunar Eclipse
It is a region where light rays can't reach.
A small light source produces a sharper shadow than a larger source. There is usually a dark part on the inside and a lighter part around the edges of a shadow. An umbra is a total shadow. It is formed when an object blocks all the light from a light source. Most shadows, however, have a darker part on the inside and a lighter part around the edges. This lighter part is the penumbra. The penumbra can be formed when light from one source is blocked with light from another source filling in some of the shadow.
Solar Eclipse
Formation of shadow by extended source of light:
(i) When extended source is smaller than opaque body;
(ii) When extended source is bigger than opaque body.
In the first case, both umbra and penumbra are formed. However, size of umbra is very large as compared to penumbra. It is for the same reason the bulbs are not preferred as source of light as compared to tube light because they form large shadows of umbra. In the second case, both umbra and penumbra are formed. However, size of umbra is far smaller than penumbra.
Eclipses: The formation of shadows of heavenly bodies, such as moon or earth on one another is called an eclipse. There are two types of Eclipse:
(1) Lunar and
(2) Solar.
A lunar eclipse occurs when the earth's shadow falls on the moon. A solar eclipse occurs when the moon's shadow falls on the Earth.