Question

Why does light from a clear blue portion of the sky show a rise and fall of intensity when viewed through a polaroid which is rotated?

Answer 1

This phenomenon can be understood by comprehending the basic principle of light.

Light travels in the form of a wave in all the possible direction in a plane perpendicular to its direction of propagation.

When we see the sky through a polarizer screen, the polarized light is observed, thereby there is difference in intensity