Answer:
Movement in art decides how the viewer will perceive an artwork. It is the path our eyes follow or the pattern our eyes go after when we look at an art work. In art, it's extremely important to keep a viewer’s eyes engrossed in the work, and the way an artist does that is by adding movement. Without any movement, artwork is stagnant and people don't really like looking at art that looks or feel boring to them, no matter how valuable it is. If our eyes see movement happening in an art work, they are more likely to enjoy the art as they are now following a pattern or path to explore the contents of the artwork.
Refraction is the change in the direction of the wave passing from one medium to another.
The change in the direction of the propagation of any wave is due to the different speed at different points.
A far away object appears closer and a small object appears larger.
Take an example. Suppose, an object lies in water.
A far away object appears closer. The angle from which the rays of light reach the observer is larger than the angle that it makes in air.
This makes the angular size larger to the observer's eye which makes the object look larger relative what it looks in air. Similar but vice versa condition occurs in the case when a small object appears larger.
