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.
A) If the light strikes the plastic (from the water) at an angle θw, at what angle θa, does it emerge from the plastic (into the air)?
Express your answer in terms of Nw, Np, Na and θw.
B)What is the distance to the object in terms of θw and L?
Express your answer in terms of θw and L.