Question

Which is not the condition for hearing sound?

• A. There must be a vibrating body capable of transferring energy.
• B. There must be a material medium to pick up and propagate energy
• C. The medium must have a large density.
• D. There must be receiver to receive the energy and interpret it.

Answer 1

The correct option is C The medium must have a large density.

Dense molecules vibrate at slower speeds. The more dense the string is, the slower it will vibrate, and the lower its frequency will be. Instruments often have strings made of different materials. The strings used for low pitches will be made of a more dense material than the strings used for high pitches.
The more dense the medium the slower the speed of sound. For example steel is 6000 times more denser than air but 2,000,000 times more elastic than air, so sound travels 16 times faster in steel than in air.