Questions Worth Pondering

  1. Will there be sound if there is a vibrating source?
  2. Is the speed of sound in air always 330 m/s?
  3. If the obstruction is considerably small, will there still be an echo?
  4. If sound strikes a soft surface, will there be a reflection that forms an echo?
  5. If sound travels in all directions, why don’t we consider the sound that reflects off the floor/ground that we are standing on when we use the formula (speed = distance/time) to find either the speed of sound or time taken by the echoes?
  6. What is a natural frequency of an object?
  7. What is a resonance?
  8. If a dolphin emits ultrasound for echolocation, what animal will emit infrasound? Are there any advantages of using infrasound compared to ultrasound?

Exam Tips

Examiner likes to ask questions that deal with the following:

  1. Identify the concept of sound can be broken down into 3 parts – the production, the transmission and the reflection/absorption.
  2. Explain how sound is transmitted in a medium (solid, liquid and gas) between the source and the receiver.
  3. Explain how sound is produced.
  4. Calculate the time difference between subsequent echoes in a scenario of a cliff or a man standing between two walls.
  5. Calculate the depth of an ocean using the concept of an echo.
  6. Explain the attenuation of sound as it travels in the a medium. Popular scenario is the reduction of sound intensity in a graph that plotted for a sonar to determine the depth of an ocean.


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