The Light List indicates that a light has a nominal range of 10 miles and is 11 feet high. If the visibility is 5 miles and your height of eye is 20 feet, at what approximate distance will you sight the light?

Correct Answer: Option A — 6.3 miles

Geographic range is the sum of the distance to the horizon for the light's height and the observer's height of eye. Using the formula 1.17 times the square root of height in feet, the total distance is 1.17(sqrt(11) + sqrt(20)), resulting in approximately 9.1 miles. Visibility limits this to 5 miles.