Question

why shadow is black colour only

Answer 1

If there is a single light source, and the shadow is being cast by an opaque object between that lignt and the surface, the shadow will be black because no light is reaching the surface where it is blocked by the object. ... The cast shadow (on a white background) will be the color of the object.

Answer 2

Shadow is in fact an area which blocks the path of light. Shadow is not a real object. Only real objects can reflect light. Shadow cannot reflect light ,so, it's black in color.

Hope it helps!!!!