Tiêu đề Class 09 Science Chapter 12 Sound.pdf ✅

Sound DPP-01 [Topic: Production and Propagation of Sound] Very Short Answer Type Questions 1. What happens to sound when it goes from solid to gaseous state? 2. How are the wavelength and frequency of a sound wave related to its speed? 3. What is the frequency of a wave whose time period is 0.025s ? 4. Which wave property determines (aa) loudness, (bb) pitch of sound waves? 5. What is the nature of sound waves? 6. A baby recognises her mother's sound by her voice. Name the characteristic of sound involved. 7. Give one example each for transverse and longitudinal waves. 8. On what factors does quality of sound depend? 9. The frequency of a source of sound is 200Hz. How many times does it vibrate in a minute? 10. Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend? 11. What is the frequency of a sound wave whose time period is 0.05 seconds? 12. What is the audible range of human beings? 13. What is the SI unit of frequency? Give its bigger unit also. Short Answer Type Questions-1 14. How does the sound produced by a vibrating object in a medium reaches your ear? [NCERT] 15. A sound wave has a frequency of 2kHz and wavelength of 35cm. How long will it take to travel 1.5km ? 16. In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature? 17. What are infrasonic and ultrasonic sounds? 18. The following figure shows the wave shapes of two sounds of some frequency. Which of these is likely to represent the sound of a car horn?
19. Why are sound waves called mechanical waves? 20. Why is light not a mechanical wave? 21. Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why? 22. Give four characteristics of sound waves. 23. Draw a diagram showing density or pressure variation in sound waves. 24. Which characteristic of sound determines its (aa) pitch (bb) loudness? Short Answer Type Questions-II 25. Explain an activity with a labelled diagram to prove that sound needs a material medium for propagation. 26. Explain how sound is produced by your school bell. 27. How longitudinal waves are produced in a slinky? 28. What are wavelength, frequency, time period and amplitude of a sound wave? 29. A wave is moving in air with a velocity of 340m/s. Calculate the wavelength, if its frequency is: (i) 512 vibrations per second (ii) 100Hz. Long Answer Type Questions 30. How transverse waves are produced in a slinky? Give one another example of transverse waves? Explain with the help of a diagram. 31. Give four differences between transverse waves and longitudinal waves and give one example of each.
Sound DPP-02 [Topic: Reflection of Sound, Echo] Very Short Answer Type Questions 1. Does sound follow the same laws of reflection as light does? 2. Write the full form of SONAR. 3. Which instrument measures the intensity of sound? 4. Which scale is used to measure intensity of earthquake? 5. Give two examples of mechanical waves. 6. If the source of sound produces 1000 compressions and 1000 rarefactions in air in 25 seconds, find the frequency of sound produced. 7. In an experiment to verify the laws of reflection of sound the angle of reflection in the figure depicted is ___________. 8. If the reflected and incident sound waves are at 90∘ with respect to respect to each other, what is the angle of incidence? 9. A pulse travels through a slinky 10m long from one end to the other end and then back to the point of origin in 3 seconds. What is the velocity of pulse in the slinky? 10. Which quantity is transferred through the medium during the propagation of sound waves? 11. How a pulse can be generated? 12. For the reflection of sound by a metal plate, which graph shows the correct relation between the angle of incidence and the angle of reflection?