Question

Three identical towels of red, blue, and green colour are hanging on a clothesline in the Sun. What would be the colour of the shadows of these towels?

Answer 1

Shadow formation:
When light is blocked in its path by an opaque object, the object's dark reflection, i.e., its shadow, casts on the screen.

Colour of the shadow:
A shadow is merely darkness, i.e., the absence of light. The colour of the shadow is independent of the colour of the object. Hence the colour of the shadow of the three coloured towels (red, blue, and green) will be the same.​