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Electromagnetic Waves and Communication System — Physics STD 11 Science — Question

Maharashtra BoardEnglish MediumSTD 11 SciencePhysicsElectromagnetic Waves and Communication System3 Marks
Question
What are ultraviolet rays? Give two uses.
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Answer

Production:

  1. Ultraviolet rays can be produced by the mercury vapour lamp, electric spark and carbon arc lamp.
  2. They can also be obtained by striking electrical discharge in hydrogen and xenon gas tubes.
  3. The Sun is the most important natural source of ultraviolet rays, most of which are absorbed by the ozone layer in the Earth’s atmosphere.

Uses:

  1. Ultraviolet rays destroy germs and bacteria and hence they are used for sterilizing surgical instruments and for purification of water.
  2. Used in burglar alarms and security systems.
  3. Used to distinguish real and fake gems.

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