NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

Clear incandescent lamps are classified as which type of source?

1. Point source

2. Linear source

3. Surface source

4. Compact source

The correct answer is: Point source

Clear incandescent lamps are classified as a point source because they emit light from a single, localized area or point. The light radiates outward in all directions, creating a uniform sphere of illumination around the lamp. This characteristic defines point sources, which are often modeled in lighting calculations and designs as having all their light output emanating from one specific point in space. In contrast, linear sources, such as fluorescent tubes, emit light along a length, while surface sources involve light emitted over a larger area, and compact sources might combine both point and linear characteristics. However, the key distinguishing feature of clear incandescent lamps is their localized light emission, affirming their classification as a point source.