Give reasons for the following: The reverberation time of a hall used for speeches should be very short

cbse
sound
cbse-class-9-science

#1

Give reasons for the following:

  • The reverberation time of a hall used for speeches should be very short.
  • A vibrating body produces sound. However no sound is heard when a simple pendulum oscillates in air.
  • Sounds of same loudness and pitch but produced by different musical instruments like a violin and flute are distinguishable.

Answer:

  • If the reverberation time of a hall is long, then the multiple echoes will enterfere with original sound. For this reason nothing will be heard distinctly. So, the reverberation time of the hall should be very short.
  • A sound is heard only if the body vibrates with a frequency more than 20 Hz and less than 20,000 Hz. The pendulum oscillates with a frequency less than 20 Hz. Hence, ho sound is heard.
  • This is due to the quality or timbre of sound waves.