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3. 1.What is meant by the term: ultrasound sound waves with a frequency above 20,000Hz answer

4. 2.What is the speed of light in air? 300,000,000ms answer

5. 3. A car has a parking sensor that emits ultrasound waves. They have a frequency of 40kHz..Calculate their wavelength answer

6. 4. A car stops 1.7m from a wall. Calculate the time for an ultrasound pulse from a parking sensor to reflect from the wall and return to the car. answer

7. 5. The car moves further from the wall, what happens to the time taken for the Ultrasonic wave to return to the car? The time will increase as it has further to travel answer

8. 6. Why can we get a good radio signal in hilly areas but a poor TV signal? Radio waves have a longer wavelength than TV waves and diffract more answer

9. 7. What is meant by the frequency of a wave? Number of complete waves that pass a point in one second answer

10. 8. Are light waves transverse or longitudinal waves? Transverse answer

11. 9.What is the frequency range of human hearing? 20Hz-20,000Hz answer

12. 10.What is the threshold of pain for the human ears? 130dB answer

13. 11. Give a use of ultrasound in medicine. Scanning an unborn baby in the womb answer

14. 12. True or false…Long wave are diffracted more than short waves? True answer

15. 13. How could we protect our hearing from becoming damaged? Wear ear muffs (ear protectors) that absorb some of the sound energy. answer

16. 14. Which sound has a higher pitch: a high frequency wave or a low frequency wave? High frequency High frequency answer

17. 15. Why can sound not travel in a vacuum? There are no air particles to carry the vibrations. answer

18. 16. The frequency of a wave is 200Hz, Calculate the Period of this wave.. answer