Sound and acoustics

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Across
  1. 2. is the number of cycles of vibration per second. The unit is the hertz
  2. 3. sound of only one frequency, such as that given by a tuning fork or electronic signal generator
  3. 4. frequency too low for human hearing
  4. 6. examples include loudspeakers, guitar strings, vibrating walls and human vocal chords.
  5. 8. examples include horns, organ pipes, mechanical fans and jet engines.
  6. 9. high frequency
  7. 11. is the distance between any two repeating points on a wave. The unit is the metre
  8. 14. 440 Hz
  9. 16. compresses adjacent particles of air as it moves in one direction and leaves the particles of air ‘spread out’ as it moves in the other direction
  10. 19. low frequency
  11. 20. frequency too high for human hearing
Down
  1. 1. The mechanical vibrations of sound move forward
  2. 5. variation in the pressure of the air of a type which has an effect on our ears and brain
  3. 7. The nature of a sound wave, such as shown in the earlier figure, means that the vibration of the wave has alternate changes in amplitude called phases
  4. 10. is the distance moved per second in a fixed direction. The unit is metres per second
  5. 12. range of frequencies between any one frequency and double that frequency
  6. 13. Every object has a natural frequency which is the characteristic frequency at which it tends to vibrate when disturbed
  7. 15. 880 Hz
  8. 17. 1320 Hz
  9. 18. frequency of a sound as perceived by human hearing.