NCIDQ IDFX Practice Exam

What is the relationship between lamp life and efficiency in incandescent bulbs?

1. Longer lamp life translates to higher efficiency

2. Higher efficiency results in shorter lamp life

3. They are generally unrelated

4. Shorter lamp life correlates with greater lumens output

The correct answer is: Higher efficiency results in shorter lamp life

The relationship between lamp life and efficiency in incandescent bulbs is one where higher efficiency often results in shorter lamp life. Incandescent bulbs produce light by heating a tungsten filament until it glows, but this process generates a significant amount of heat, which can lead to a decline in the filament's integrity over time. In an effort to enhance efficiency, manufacturers may produce bulbs that are designed to operate at higher temperatures or use different materials that facilitate more lumens output per watt consumed. However, these modifications can contribute to an increased rate of degradation of the filament, ultimately resulting in a shorter lifespan for the bulb. This means that while these more efficient bulbs may provide more light output for the energy used, they often cannot sustain that performance over a long period, thereby reducing their overall lifespan. Understanding this relationship is key for designers selecting appropriate lighting solutions, as they must balance the immediate benefits of higher lumens output with the practical implications of replacement frequency and ongoing maintenance costs associated with shorter-lived bulbs.