Navigation General · Light Characteristics
An 'isophase' light shows:
- ALight and darkness of equal duration✓ Correct
- BTwo colors alternating
- CA continuous quick flash
- DLight only at dawn
Explanation
Isophase (equal interval) lights have equal periods of light and darkness. This distinguishes them from occulting (more light than dark) and flashing (more dark than light) characteristics on the chart and in the Light List.
Authority: USCG Light List
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