Luxsecond

Luxsecond is a unit of illuminance, which is a measure of how much luminous flux is incident on a surface. It is the product of the illuminance and the duration over which it is measured. Specifically, one luxsecond is equal to the illuminance of one lux applied over a period of one second.

The unit luxsecond is derived from the SI units for illuminance and time. Lux (lx) is defined as one lumen per square meter (lm/m²), and time is measured in seconds (s). Therefore, a luxsecond has units of lumens per square meter per second (lm/(m²·s)).

While lux is a commonly used unit for measuring the brightness of light on a surface, the luxsecond is less frequently encountered in everyday contexts. It finds application in specialized fields where the cumulative effect of light over time is important. For example, it can be used in scientific research, particularly in areas such as photobiology, where the total light exposure is a critical factor in biological processes. It may also appear in the specifications of certain optical or light-sensitive equipment where the integrated light dose is a relevant parameter.

The concept of luxsecond is analogous to other derived units that combine a rate with a duration, such as watt-hour (energy) or joule-second (angular momentum). It provides a way to quantify the total light stimulus received by a surface over a specific interval.