Analysis of information sources in references of the Wikipedia article "Luminous efficacy" in English language version.
If the lamp emits all radiation at 555 nm (where Vλ = 1), the luminous efficacy will be of about 680 lm W−1, the theoretical maximum value. The lamp efficacy will be 26 and 73 lm W−1, when the whole light is emitted at 450 and 650 nm respectively. The luminous coefficient is luminous efficiency expressed as a value between zero and one, with one corresponding to an efficacy of 683 lm W−1.
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