Q2. 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 a longer life span than LED lamps.
- The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant color advantages in street lighting.
Select the correct answer using the code given below.
a) 3 only
b) 2 only
c) 1 and 3 only
d) 1, 2 and 3
Answer: (c)
- The first statement is true. Sodium lamps emit light in all directions, whereas LED bulbs do not. The 180-degree bulb angle of LED lamps maintains light efficiency and enables area-target lighting.
- The second claim is untrue. As street lights, sodium lamps typically last less time than LED bulbs. High-pressure sodium lamps typically last for 24,000 hours on average. While the lifespan of an LED lamp is between 25,000 and 200,000 hours.
- The third statement is true. Due to their well-known warm yellow glow, sodium lamps provide almost monochromatic visible light. However, when it comes to street lighting, LED bulbs have substantial color advantages. Better illumination options are provided by LEDs’ range of color possibilities.
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