What are characteritics of lights ?

Characteristics of Lights are:

1. Fixed light (F) – continuous steady light.
2. Flashing Light – shows single flash at regular interval, the duration of light always shorter than the duration of darkness not more than 30 flashes per minute.
3. Group Flashing (GP FL) – shows groups of two or more flashes at regular intervals.
4. Quick flashing (QK FL) – shows not less than 60 flashes per minute.
5. Interrupted Quick Flashing (I QK FL) – shows quick flashes for about 4 seconds followed by a dark period of about 4 seconds.
6. Short Long Flashing (S L FL) – shows short flashes of about 0.4 second followed by a long flash of about 4 seconds in duration.
7. Group Occulting (GP OCC) – a light with a group of two or more eclipse.