Light intensity is the quantity of light. It can be measured in two different ways: instantaneous or cumulative.
Instantaneous light measurement tells us how much light a plant is receiving at that exact moment. So the measurement of instantaneous light at sunset will be different from the measurement at noon.
Cumulative light measurement tells us how much light a plant received in one day. So the measurement at noon does not matter because it is contributing to the cumulative measurement of light for the entire day.
If a plant does not receive enough light, it won’t have enough light energy to produce energy through photosynthesis. But if you give a plant too much light, they won’t be able to bring in enough water to keep up and they could dry out.