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1 question · 2021 · answers as per the UPSC key

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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.

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
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Answer: (c) 1 and 3 only