When is a vessel operator required to use navigation lights? at all times when moored at a dock or pier when away from the dock during the day during periods of restricted visibility

A vessel operator is required to use navigation lights at all times under the listed conditions, however, the required lights vary for the different conditions listed. The various lights provide other vessel operators with important information.

Explanation:

When moored at dock, the operator must display a white light visible in all directions as well as when anchored outside a designated mooring area between sunset and sunrise.

During a period of restricted visibility such as fog, operator must display Red and green sidelights visible from a distance of at least two miles away

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me