How do you measure light intensity?

Explanation:

1. A light metre (also known as an illuminance metre or lux metre) is used by lighting professionals to measure the quantity of light in an area or on a specific work surface. A sensor on the light metre monitors the amount of light falling on it and provides the user with a measured illuminance reading.
2. Luminance is the apparent brightness of an object as seen by the human eye. When we gaze at the world, we observe a pattern of varied luminance (ignoring the colour component).

Draw a diagram,

Therefore,

1. In physics, light intensity or luminous intensity is the amount of light that falls on a surface across a certain square foot or square metre.
2. The intensity of light is measured in lumens per square foot (footcandles) or lumens per square metre (lux).

Hence, this is the way to measure light intensity.