Radiance refers to the brightness or light emitted from a source. It is a measure of how much light is produced and can be observed in various forms, such as sunlight, artificial lights, or glowing objects. Radiance is often quantified in terms of intensity and is important in fields like physics, photography, and astronomy. In physics, radiance is defined as the amount of light energy that passes through a given area in a specific direction. It is commonly used to describe the properties of light sources, including lasers, LEDs, and stars. Understanding radiance helps in applications like optics and imaging technology.