According to this function, 700 nm red light is only about 0.4% as efficient as 555 nm green light. Thus, one watt of 700 nm red light is "worth" only 2.7 lumens.OverviewPhotometry is a branch of that deals with measuring in terms of its perceived to the. It is concerned with quantifying the amount of light that is emitted, reflected, transmitted, or received by an objec. The is not equally sensitive to all of. Photometry attempts to account for this by weighting the measured power at each wavelength with a factor that represents how sensitive the eye is a. Measurement of the effects of electromagnetic radiation became a field of study as early as the end of the 18th century. Measurement techniques varied depending on the effects under study and gave rise t.
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