What is the light intensity

If a light meter can be used, it can measure light sources at different distances. Then you will find that as the distance between the light source and the illuminometer increases, the light intensity will decrease. You can understand the relationship between the physical laws of light intensity and the distance to the light source.
Manufacturers can place the growth lamp at a higher position above the vegetation and illuminate a larger footprint. Then, if the LED is designed to emit light close to the plants, the output will be higher. The light intensity at the edges is lower.
Leaf tissue can touch well-designed LEDs because their operating temperature is low enough, so the tissue will not be harmed in any way. Therefore, you can bring these lights closer to the plants. Although light intensity is a limiting point, too much can burn plant tissue.