Question

The portion of shadow that receives no light is the __________ and the portion that receives light from a part of the source is the ____________.

• A. Umbra
• B. Penumbra

Answer 1

When a wide source of light is used,

1. A dark shadow is formed at the centre where no light is reached and is called an umbra.
2. The light shadow formed around the umbra is called a penumbra where a part of the light from the source is reached.

Hence, the portion of shadow that receives no light is the umbra and the portion that receives light from a part of the source is the penumbra.