NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

Light output is measured in?

1. Footcandles

2. Lumens

3. Watts

4. Electrons

The correct answer is: Lumens

Light output is measured in lumens, which quantify the total amount of visible light emitted by a source per unit of time. This measurement reflects how bright the light appears to the human eye, regardless of the technology used to produce that light. Footcandles represent illuminance, which indicates the amount of light that falls on a surface from a light source, but this is not a measure of the light output itself. Watts are a measure of power consumption and do not directly correlate to the perceived brightness of the light emitted. Electrons are subatomic particles that make up atoms and are not a measurement used in the context of light output. Thus, lumens are the appropriate unit to describe how much light is being produced by a lighting fixture.