The Light List indicates that a light has a...

Question 1 of 2921866636ee928f7522a1c519a8f

The Light List indicates that a light has a nominal range of 14 miles and is 26 feet high. If the visibility is 4 miles and your height of eye is 20 feet, at what approximate distance will you sight the light?

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Question 1 of 29218

🔍 Key Concepts

• Difference between nominal range and geographic range of a light • How meteorological visibility affects the luminous range of a light • Using the distance to the horizon formula for both the observer and the light

💭 Think About

• First, consider whether you can use the full nominal range when visibility is only 4 miles. How does that limit what you can see? • Next, figure out how far away the light could be before the curvature of the Earth hides it. You’ll need the height of the light and your height of eye for this step. • After you find the maximum distance at which the light and your eye can see each other over the horizon, compare that with what the visibility allows. Which limitation will control the actual sighting distance?

✅ Before You Answer

• Be sure you understand that nominal range assumes 10-mile visibility, which is not the case here. • Calculate the geographic range using an appropriate horizon-distance formula for both the light and the observer, then add the two distances. • Finally, compare the geographic range with the range limited by 4-mile visibility, and use the smaller of the two to match the closest answer choice.