🔍 Key Concepts

• Luminous (nominal) range vs. geographic range of a light • How to compute geographic range using heights of eye and light (distance to the horizon) • Limiting range: comparing nominal range and geographic range to see which one controls how far away you can actually see the light

💭 Think About

• First, think about what the 10‑mile nominal range actually represents and what visibility of 15 miles tells you about whether nominal range is your real limit here. • Next, recall the approximate formula or table method for distance to the horizon based on height in feet; you’ll need it once for the light and once for your eye. • After you find the geographic range for the light and your eye, compare that geographic range to the nominal range: which one is smaller, and how does that affect the maximum distance at which the light can be seen?

✅ Before You Answer

• Be sure you are using the correct horizon-distance formula or table for height in feet, and keep track of units in nautical miles. • Confirm whether visibility (15 miles) makes the 10‑mile nominal range more or less important in this problem. • Check that your final distance is consistent with the idea that the actual visible range is limited by the lesser of nominal range and geographic range.