NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

In terms of efficiency, an incandescent lamp typically converts what percentage of its electrical input into light output?

1. 10-15%

2. 20-25%

3. 30-35%

4. 50%

The correct answer is: 10-15%

Incandescent lamps are known for their relatively low efficiency compared to other lighting technologies. Typically, they convert about 10-15% of the electrical energy they consume into visible light. The rest of the energy is lost primarily as heat. This inefficiency is a primary reason why other types of lighting, such as compact fluorescent lamps (CFLs) and light-emitting diodes (LEDs), have gained popularity, as they convert a higher percentage of energy input into light output. The stated range of 10-15% accurately reflects the performance of incandescent lamps, making it the correct response in this context.