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