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JAMB Physics 2004 Question 25

Question 25

Conduction through Liquids and Gases

Fluorescent tubes produce light by the

  1. A.refraction of light by gas molecules.
  2. B.excitation of gas molecules.
  3. C.conduction of solar energy.
  4. D.thermal agitation of electrons in the tube.
Show the answer and explanation

Answer: B (excitation of gas molecules.)

Explanation

Electrons excite the gas (mercury vapour) atoms; as they return to lower levels they emit radiation that makes the coating glow.