NALMCO Certified Apprentice Lighting Technician (CALT) Practice Exam

If a lamp produces 3000 lumens and the ballast has a ballast factor of 0.90, what is the lamp's light output when operated by the ballast?

1. 3000

2. 2700

3. 2500

4. 3236

The correct answer is: 2700

To determine the lamp's light output when operated by the ballast, it's essential to understand the relationship between the lamp's lumen output and the ballast factor. The ballast factor represents the influence that the ballast has on the light output of the lamp. In this case, a ballast factor of 0.90 means that the ballast will allow the lamp to operate at 90% of its rated output. Given that the lamp generates 3000 lumens under optimal conditions, the calculation involves multiplying the lamp's lumen output by the ballast factor: Light Output = Lamp Lumen Output × Ballast Factor Light Output = 3000 lumens × 0.90 = 2700 lumens Thus, when the lamp is operated with a ballast that has a factor of 0.90, its effective light output is reduced to 2700 lumens. This value reflects the actual illumination provided by the lamp when powered by this particular ballast, showcasing the impact that ballast efficiency has on lighting systems.