If you have a larger aquarium, chances are your accompanying light fixture contains long bulbs and probably a couple of them.
Light Intensity and Output: Regarding light intensity and output, more light output is required with larger and deeper tanks, as lumens decrease with distance and some light wavelengths plants require do not penetrate water as well as others. If you have a larger aquarium, chances are your accompanying light fixture contains long bulbs and probably a couple of them. Together, this will keep the length of the tank well lit with intensity high enough for your plants.