Lumens define which aspect of lighting?

• A. Measured light output from a light
• B. Brightness level in watts
• C. Color temperature in kelvin
• D. Luminous intensity in candelas

Answer: (A)

Lumens measure the total amount of visible light a source emits, known as luminous flux. This reflects how much light is produced by the bulb overall, which helps you compare brightness across different bulbs. Watts, by contrast, indicate energy consumption, not brightness. Color temperature in kelvin describes whether the light looks warm or cool, not how much light there is. Luminous intensity in candelas measures light emitted in a specific direction, which matters for directional lighting but not the total output. So lumens are the best descriptor of how much light a fixture produces in total.