In what unit is lamp output typically rated?

Lamp output is typically rated in lumens, which is a measurement of the total amount of visible light emitted by a lamp. This unit quantifies how much light is actually produced and is essential for understanding how bright a light source will feel in a given environment. When selecting light fixtures, the lumen rating helps determine how well a space will be illuminated.

Watts, on the other hand, measure the energy consumption of a lamp rather than its light output, making it less applicable when discussing brightness directly. Volts are a measure of electrical potential, and amperes measure the flow of electric current; neither of these units provides information about the intensity of light produced by a lamp. Thus, lumens are the appropriate unit for lamp output, making it the correct choice for this question.