🔍 Key Concepts
• Meaning of light abbreviations on charts, especially Gp Fl, R, and the number in parentheses
• How period of a light is expressed (full on-and-off cycle) versus the number of flashes
• Difference between range of visibility (M) and height (ft) on a light description
💭 Think About
• Break the symbol into parts: Gp Fl, R, (2), 10 sec, 160 ft, 19M. Ask yourself what each segment normally describes: color, rhythm/grouping, period, height, or range?
• Compare the meaning of the period (10 sec) with choice A: is it the total cycle time or just the time the light is on?
• Think about what unit is normally used for nominal range of a light on charts, and whether "2 nautical miles" matches the notation in the symbol.
✅ Before You Answer
• Confirm what Gp Fl stands for and how it differs from a single flash light
• Verify what the M after a number means in light characteristics (is it meters, miles, or something else in this context?)
• Confirm whether the letter R in light characteristics refers to color, rhythm, or something different