🔍 Key Concepts

• Geographic range vs. luminous range of a light (which one depends on visibility, which one depends on height of eye and height of light) • Meaning of the phrase "break the horizon" in terms of the curvature of the Earth and distance to the horizon • The standard distance to horizon formula using height of light (and possibly height of eye) in nautical miles

💭 Think About

• Is the limiting factor in this problem the light’s brightness (visibility 27 nm) or the Earth’s curvature (distance to the horizon)? • When a question says a light will "break the horizon," are you dealing with luminous range or geographic range? • Which answer choice is in the typical range you get when you compute geographic range for a light of moderate height (tens of feet) on a standard training chart?

✅ Before You Answer

• Be sure you are using geographic range, not the 27 nm visibility, to pick the distance where the light first appears over the horizon. • Confirm how "break the horizon" is defined in your Bowditch/Light List reference so you choose the correct type of range. • Think about typical horizon distances (in nm) for lights 30–80 feet above sea level and eliminate choices that are clearly too small or too large for that range.