Question

why can light pass at top half but not at bottom half of this container??

Answer 1

It is bcoz the window frame is covering the lower half of the container which blocks the light to pass that specific part of the container

Answer 2

actually light cannot pass through the half of the bottle as the bottle is opaque.. light is coming from the sides and surrounding the bottle ...
At bottom there is no light available.....

Hope this helps u dear friend