Home PYQs UPPSC UPPSC MCQs Prelims 2007 (GS Paper I)

Question

Sodium vapor lamps are used in road lighting because

  1. They are cheap
  2. Their light is monochromatic and does not scatter when passing through water droplets
  3. It's cool for eyes
  4. It gives brightness in light

Answer:

Option B: Their light is monochromatic and does not scatter when passing through water droplets

Detailed Solution:

The correct answer is “Their light is monochromatic and does not scatter when passing through water droplets”.

The reason sodium vapor lamps are used in road lighting is because their light is monochromatic and does not scatter much when passing through water droplets. This reduces glare and improves visibility during rainy conditions.