Which description matches an Isophase light?

• A. Flashing light
• B. Occulting light
• C. Isophase, equal light/dark
• D. Fixed light

Answer: (C)

Isophase light means the light is on for the same amount of time as it is off in each cycle. That 50/50 duty cycle creates an even, steady rhythm, with no abrupt bursts or unusually short/long dark gaps. So the description that matches is the one describing equal light and dark intervals.

This differs from a flashing light, where brief light pulses are separated by longer darkness; an occulting light stays on for a long time and then briefly goes dark; and a fixed light stays on continuously with no dark phase at all.