Question

describe the umbra and penumbra of a shadow. show that when the light source is a point source only umbra is formed​

Answer 1

Answer:

Umbra is the part of the the shadow in which no light reaches to it as the opaque object is placed in front of the portion of screen.

Penumbra is the portion of the shadow in which some dim light pases through it and it does not have any sharp edges.

As we have to illuminate an opaque object with a point source of light .