1. The
SI unit of
illuminance, symbol
lx, equal to one
lumen per metre squared. The plural is unchanged lux.
Average light intensities are, very roughly:
- 100 lx inside a house
- 300 ~ 500 lx in a workplace
- 2 000 lx outside on a dull winter's day
- 10 000 lx outside on a bright summer's day
The
eyes adjust so that the difference in illuminance does not seem so enormous; also (thanks,
Oolong) illuminance is perceived logarithmically.
2. A brand of soap. (You knew that.)