Technical Comparison of Sodium and LED Street Lamps
Question
With reference to street-lighting, how do sodium lamps differ from LED lamps?
- 1.
Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
- 2.
As street-lights, sodium lamps have longer life span than LED lamps.
- 3.
The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street-lighting.
Options
3 only
2 only
1 and 3 only
1, 2 and 3
Explanation
Statements 1 and 3 are correct. Sodium vapor lamps emit light in all directions (360 degrees) and produce a nearly monochromatic yellow light. In contrast, LEDs are directional light sources and offer excellent color rendering profiles. Statement 2 is incorrect because solid-state LED systems have a much longer operational life span (>50,000 hours) than traditional gas-discharge sodium lamps. > LEDs provide directional illumination and better color rendering with a significantly longer lifespan than sodium lamps. Answer: (c).
Question details
Year
2021
Paper
GS Paper 1
Question
Q72
Subject
Science & Technology
Sub-topic
Physics & Chemistry (basic)
Type
Statement-based
Difficulty
Hard
Nature
Static
Source hint
Lighting technologies comparative physics
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