The light rays are refracted by the cornea onto the lens. The light rays are refracted a second time whilst passing through the lens and focussed onto the retina â the light sensitive part of the eye. The image formed on the retina is inverted (upside down) and real (the light rays travel through the image).
Nationally, professionally-installed radon mitigation system costs average $1,200, but range from $800 to $1,200 in Colorado, assuming there aren't any problems encountered during installation.*. Costs are highly dependent on what is required to vent the radon and how to route it through the house.
Typical costs: 1  A radon test kit, including laboratory analysis, costs $15-$35. 2  Just sealing cracks and holes in the foundation can cost as little as $100, but this method alone has limited effectiveness. 3  Passive and active suction systems cost $550-$2,500 depending on the size of the house.