Which term describes the measure of light power emitted from a source?

Luminous flux is a measure of the total amount of visible light emitted from a source per unit time, quantified in lumens. It encompasses all the light emitted in all directions, providing a comprehensive measure of how bright a light source appears to an observer.

This term is crucial in the field of lighting design and photometry because it helps in quantifying the output of light sources for applications such as artificial lighting, ensuring that spaces are adequately illuminated based on their intended use. The focus on luminous flux enables the comparison of different light sources in terms of their brightness and effectiveness.

In contrast, luminous intensity refers to the power emitted by a light source in a particular direction, while luminous efficacy measures how well a light source converts electrical power into visible light, and luminous energy represents the total light energy emitted over time. These terms, while related, serve different purposes and cannot be used interchangeably with luminous flux.