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JAMB Physics 1999 Question 27

Question 27

Electromagnetic Spectrum

Which of the following electromagnetic waves is least energetic?

  1. A.Infra-red rays
  2. B.X-rays
  3. C.Ultra-violet rays.
  4. D.Gamma rays.
Show the answer and explanation

Answer: A (Infra-red rays)

Explanation

Photon energy rises with frequency. Of these, infra-red has the lowest frequency, so it is the least energetic; gamma rays are the most energetic.