Question

A light wave encounters a partial physical barrier, such as a wall with a hole in it. What is MOST LIKELY to occur?

Answer 1

The light will be diffracted. 
diffraction - bending of a wave in a homogeneous medium around obstacles or through a narrow opening.

hope this helps :)

Answer 2

Most likely, the light wave will be absorbed by the wall. Without any information as to the size and color of the wall, the location and size of the hole, or the location of the light wave, this is a generalized probability problem. For all of the places the light could be, it's more likely that it hits the wall than the hole (if the hole is less than 50% of the area of the wall).