Light intensity refers to the amount of light energy that reaches a surface per unit area. It is commonly measured in units like lux or lumens. Higher light intensity means more light is available, which can affect visibility and the growth of plants, as seen in photosynthesis. Factors influencing light intensity include the distance from the light source and any obstacles that may block the light. For example, moving further away from a light bulb reduces the intensity of light received. Understanding light intensity is essential in fields like photography, agriculture, and architecture.