A girl walking in the midday sun and could see her small shadow following her. There was a plane flying high overhead but it threw no shadow on the ground. Why?
If an object is placed between a source of light and a screen, a shadow falls on the screen. If the object is smaller than the source of light then the shadow will have a small dark centre called umbra and a larger and lighter shadow surrounding it called the penumbra.
The further you move the object from the screen and towards the source of light, the smaller the umbra. If you take it very far from the screen, the umbra disappears.
The plane high in the sky is the object between the source of light (sun) and the screen (ground). It’s too far away from the screen so there’s no umbra and the penumbra is so faint that it cannot be seen.
Picture Credit : Google
