We cannot see things behind a wall because light travels in a straight line . This is called as the rectilinear propagation of light.
A) We aren't able to see through a wall. This suggests us that light can not travel through opaque solids, so the light that reflects off our eyes, hits the wall and gets reflected again, instead of seeping through it, making us unable to see through the wall.
B) A better example of translucent material is butter paper.
b)We are not able to see things behind a wall as it is a opaque object through which we cannot see...
hope it helps u
plastic is a translucent material because we can see something behind it but not clearly
(ii) we can't see any thing behind wall because it is an opaque thing it absorbs light