With reference to street-lighting, how do sodium lamps differ from LED lamps?
- Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
- As street lights, sodium lamps have longer life span than LED lamps.
- The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street-lighting.
Select the correct answer using the code given below.
[UPSC Civil Services Exam – 2021 Prelims]
(a) 3 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3
- Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps. LED lamps have 180-degree bulb angle to preserve light efficiency and allow for target lighting over areas. Statement 1 is correct.
- As street lights, sodium lamps have on an average shorter lifespan than LED lamps. High Pressure Sodium lamps tend to have a lifespan averaging 24,000 hours. Whereas, LED lamps lifespan ranges from 25,000 to 200,000 hours. Statement 2 is incorrect.
- Sodium lamps emit a nearly monochromatic visible light spectrum, resulting in a warm yellow glow. Conversely, LED lamps are superior in street lighting due to their various color options, providing better lighting solutions compared to High Pressure Sodium lamps. Statement 3 is correct.