USCG Exam PracticeLight List, ranges, and light characteristics
A light charted as 'Fl R 4s' produces what characteristic?
- ✓ A single red flash every 4 seconds, with the period of light shorter than the period of darknessCorrect
- B. A red light that is on for 4 seconds and off for 4 seconds
- C. A continuous red light interrupted by a short eclipse every 4 seconds
- D. Three red flashes grouped together every 4 seconds
Why A is correct
Flashing (Fl) is defined as a single flash regularly repeated where the duration of light is shorter than the duration of darkness. The characteristic string 'Fl R 4s' denotes a red flash with a 4-second period. Equal on/off describes Isophase; continuous light with eclipses describes Occulting.