Alight bulb's brightness is reduced when placed behind a screen. the amount of visible light produced by the light bulb decreases by 25% with each additional layer that is added to the screen. with no screen, the light bulb produces 750 lumens. the lumen is a unit for measuring the total quantity of visible light emitted by a source. select the correct equation that can be used to represent the lumens, l, after x screen layers are added.