Question

Your eye is designed to work in air. Surrounding it with water impairs its ability to form images. Consequently, scuba divers wear masks to allow them to form images properly underwater. However, this does affect the perception of distance, as you will calculate. Consider a flat piece of plastic (index of refraction np) with water (index of refraction nw) on one side and air (index of refraction na) on the other. If light is to move from the water into the air, it will be refracted twice: once at the water/plastic interface and once at the plastic/air interface.

Answer 1

Refraction is the adjustment in bearing of a wave going starting with one medium then onto the next or from a progressive change in the medium.  

Explanation:

Refraction is the bowing of a wave when it enters a medium where its speed is extraordinary. The refraction of light when it goes from a quick medium to a moderate medium twists the light beam toward the ordinary to the limit between the two media.  

We have discovered that refraction happens as light goes over the limit between two media. The transmission of light over a limit between two media is joined by a change in both the speed and wavelength of the wave. Due to refraction of light, the article gives off an impression of being raised when set submerged.