Arrange the following electromagnetic waves in the order of their increasing wavelength:
  1. $\gamma- \text{rays}$.
  2. Microwaves.
  3. X-rays.
  4. Radio waves.
How are infra-red waves produced? What role does infra-red radiation play in (i) Maintaining the Earth’s warmth and (ii) Physical therapy?
CBSE OUTSIDE DELHI - SET 3 PANCHKULA 2015
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Gamma $(\gamma)$ rays, X-rays, Microwaves, Radiowaves.
Infrared rays are produced by hot bodies/vibration of atoms and molecules.
Infrared rays:
  1. Maintain Earth’s warmth through green house effect.
  2. Produce heat.
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