What is the unit used to measure light intensity that is equal to one lumen per square foot?

The unit used to measure light intensity that is equal to one lumen per square foot is known as a foot-candle. This unit specifically quantifies the amount of light that falls on a surface area of one square foot from a light source that emits one lumen. Understanding foot-candles is crucial in interior design and architectural lighting, as it helps in assessing the brightness levels necessary for different spaces based on their function.

The foot-lambert, while also a measure of light, pertains to the brightness of a surface that reflects light rather than measuring illuminance at a point. Candela is the base unit of luminous intensity and refers to the power emitted by a light source in a particular direction. Lux is the metric unit that measures illuminance in terms of lumens per square meter, but it is not equal to lumens per square foot, making foot-candle the appropriate term for this context.