TSFA Knowledge Based Certification Practice Test

Light intensity describes the amount of light energy hitting a plant leaf per unit area per unit time. This matters because photosynthesis relies on available light: when light intensity is higher (up to the plant’s limit), the rate of photosynthesis can increase, supporting better growth; too little light slows or stops photosynthesis and can lead to weak, elongated growth. Light intensity is influenced by how close the plant is to the light source, duration of exposure, and the quality of the light. In plant contexts you might also hear PAR, which refers to the portion of light usable for photosynthesis. The other terms come from photography or media contexts and don’t describe how much light a plant leaf receives.