Example Question #1 : Plants
The pigments in chloroplasts absorb red light and reflect green light. During photosynthesis, the absorbed light is used as energy to convert carbohydrates to ATP for the plant to use.
Under what color light would a plant grow the slowest?
The plant is only able to use absorbed light during photosynthesis; reflected light cannot be used as energy, as it is simply returned back into the surroundings. Red light will make a plant grow the fastest because it is absorbed. Since green light is reflected, growing a plant in green light will result in very slow growth. The light will effectively bounce off the plant, rather than being absorbed.