Luminous Flux

What Does Luminous Flux Mean?

Luminous flux is the measure of brightness of a light source in terms of energy being emitted. Luminous flux, in SI units, is measured in the lumen (lm). It is a measurement of energy released in the form of visible light from a light-producing source. Luminous flux is often a criteria of light bulb comparison.


Luminous flux is also known as luminous power.

Techopedia Explains Luminous Flux

Luminous flux is often mistakenly thought to be same as radiant flux, which is incorrect. Luminous flux is the energy measurement of visible light, whereas radiant flux is the total electromagnetic energy released by that source of light. Total electromagnetic energy includes all the visible as well as non-visible radiation emanating from a source. Luminous flux interprets the sensitivity of a human eye by taking the power of each wavelength present in light. A luminous function is used to describe the eye’s response to each wavelength.


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Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.