Question 1 of 2707066636ee928f7522a1c519aa1

The Light List shows that a navigational light has a nominal range of 10 miles and a height above water of 38 feet (11.6 meters). Your height of eye is 52 feet (15.8 meters) and the visibility is 11.0 miles. At which approximate range will you first sight the light?

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Question 1 of 27070
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The Light List shows that a navigational light has a nominal range of 10 miles and a height above water of 38 feet (11.6 meters). Your height of eye is 52 feet (15.8 meters) and the visibility is 11.0 miles. At which approximate range will you first sight the light?

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🔍 Key Concepts

• Geographic range vs. luminous (nominal) range of a light • How to compute distance to the horizon from a known height of eye (for both the observer and the light) • How meteorological visibility can limit the usable range of a light

💭 Think About

• First, calculate the geographic range based on the height of the light and your height of eye. What standard formula do you use on the exam for distance to the horizon in nautical miles? • Compare the geographic range you calculated with the nominal range (10 miles) and the visibility (11.0 miles). Which of these three values actually limits when you can first see the light? • Once you know which factor is limiting, check which answer choice is closest to that limiting range.

✅ Before You Answer

• Be sure you use the correct horizon-distance formula and units (feet vs. meters) that match the exam standard. • Confirm whether you must add the horizon distance of the light and of the observer to get the total geographic range. • Check which is smallest among: geographic range, nominal range (10 miles), and visibility (11.0 miles); that smallest value controls first sighting.