Brightness

The light intensity of a light source refers to the amount of light emitted by that source in a specific direction. It can be measured in different units depending on the context:

1. Candela (cd): This is the standard unit for light intensity in the direction in which the light is emitted. It indicates how much light is emitted per steradian, a unit of solid angle. The higher the number of candelas, the stronger the light source is in that direction.

2. Lumen (lm): This measures the total amount of visible light emitted by a source. It is a measure of the light output produced by the light source across all directions.

Light intensity can be influenced by factors such as the design efficiency of the light source, the shape of the reflector, and any filters or lenses that direct the light. A lamp with high light intensity will provide brighter illumination in a particular direction compared to a lamp with lower light intensity.

In summary: Light intensity indicates how bright a light source is in a specific direction, while total light output or luminous flux (measured in lumens) measures the overall amount of light produced by the source.