Final answer:
We have improved the efficiency of lighting technology from a candle's 0.3 lm/W to an LED's 100 lm/W, a factor of 333.3. There is still a factor of 3 improvement needed to reach the theoretical limit of 300 lm/W for luminous efficacy.
Step-by-step explanation:
When considering improvements in lighting technology, we look at the luminous efficacy, which is measured in lumens per Watt (lm/W). A candle has a luminous efficacy of 0.3 lm/W while a modern LED light bulb achieves around 100 lm/W. This indicates that we have improved lighting efficiency by a factor of approximately 333.3 (100 divided by 0.3), which is a significant increase in efficiency. However, compared to the theoretical limit of lighting efficiency, which is about 300 lm/W, we still have a factor of 3 to achieve (300 divided by 100).
The luminous flux is the rate at which light is radiated from a light source, and higher efficacy means more light for less power, leading to energy conservation and cost savings. With advancements in technology, we've been able to transition from incandescent to fluorescent, and now to LED bulbs, which are far more efficient. Nevertheless, the theoretical limit set by photon energy requirements suggests we may not see another doubling in efficiency any time soon.