. . . . "luminous flux"@en . _:b19771 . _:b19791 . . . . _:b19771 . . "Luminous flux is the total visible energy emitted by a source per unit time."@en . . _:b19770 . . . . "F" . . _:b19770 _:b19771 . . _:b19791 . _:b19770 . _:b19771 . . _:b19770 . . . _:b19791 . . _:b19791 . . .