USCG Exam Practice · Light List, ranges, and light characteristics
A light charted as 'Fl R 4s' displays which characteristic?
- AA single red flash every 4 seconds, with the period of light shorter than the period of darkness✓ correct
- BA continuous red light interrupted by a 4-second eclipse
- CEqual periods of red light and darkness, each 2 seconds long
- DA red light with a brighter flash superimposed every 4 seconds
Why A is correct
A Flashing (Fl) light shows a single flash regularly repeated with the duration of light shorter than the duration of darkness. The charted notation 'Fl R 4s' indicates a red flash with a 4-second period. Option B describes Occulting; Option C describes Isophase; Option D describes Fixed and Flashing.
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