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JAMB Physics 2010 Question 25

Question 25

Sound

The sound of an electric bell dies down slowly when air is slowly pumped out from a bottle because

  1. A.sound cannot pass through the bottle.
  2. B.sound can pass through a vacuum.
  3. C.sound needs a material medium.
  4. D.the wavelength of sound becomes greater in the bottle.
Show the answer and explanation

Answer: C (sound needs a material medium.)

Explanation

As air is removed there is less medium to carry the vibrations, so the sound fades. Sound needs a material medium and cannot travel through a vacuum.