What causes the fuzzy region around the edge of the shadow? or simply penumbra.?

Question

What causes the fuzzy region around the edge of the shadow? or simply penumbra.?

Answer 1

two things, the scattering of light in air as well as penumbra.

If you know what penumbra is...then you should have an idea about the scattering.

Depending on distance of object to light source and distance to shadow surface and the ratio of these distances, penumbra and light scatter will affect it in different ammounts.

Answer 2

The edge of a shadow is fuzzy due to the effects of the light being diffracted by the edge of the object that it is illuminating! The definition of the word 'penumbra' is (Latin: paenes "almost, nearly" + umbra "shadow") the region in which only a portion of the occulting body is obscuring the light source. Thus, the penumbra of a shadow is fuzzy due to the effect of 'knife edge' diffraction and shows small fringes near its edges if the diffracting edge is sharp enough and the light source is monochromatic.

Answer 3

Scattering of the light DUE TO THE AIR IN WHICH WE ALL ARe.  It is called RAYLEIGH SCATTERING and also other types of scattering but you MUST KNOW that the light waves are scattered, light beams and rays and particles too, the scattering is what makes it all happen.