| Answer | Crossword Clue |
|---|---|
| PSEC | Time it takes for light to travel .3 mm |
| PSEC | Time it takes light to travel .3 mm: Abbr. |
| NSEC | Roughly, time it takes for light to travel one ft. |
| NSEC | Approx. time it takes for light to travel one foot |
| MSEC | How long it takes light to travel 186 mi. |
| NSEC | About how long it takes light to travel a ft. |
