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Sound- Class IX-Vasu Classes

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1. In a wave motion what is transferred? a) mass b) speed c) energy d) medium

2. The sound waves are called a) mechanical waves b) elastic waves c) longitudinal waves d) all of the above

3. The time taken by a wave to travel a distance equal to its wavelength is called a) Time period b) frequency c) amplitude d) wavelength

4. A source of sound produces 40 troughs and 40 crests in 0.4s. What will be the frequency? a) 1000Hz b) 100Hz c) 10Hz d) 5Hz

5. The frequency of a wave is 20Hz and its wavelenght is 20m in amedium.The velocity of the wave will be a) 400m/s b) 40m/s c) 100m/s d) 1m/s

6. In the formation of a compression a) Volume increases b) density increases c) volume decreases d) 2 and 3

7. The speed greater than the speed of sound is called a) sonic boom b) supersonic c) ultrasonic d) infrasonic

8. The charecteristics of sound are a) Timbre b) pitch c) Range d) B & C

9. Which property of light is obeyed by sound a) reflection b) refraction c) interference d) defraction

10. Minimum time interval required to hear an echo is a) 1/15s b) 1/10 s c) 1/20 s d) none

11. Multiple reflection of sound is called a) Echo b) Sonicboom c) Explosion d) Reverberation

12. SONAR stands for a) Sound navaigation and ranging b) Sonographic navigation and ranging c) Both A and B

13. One Hertz is equivalent to a) one vibration /sec b) One cycle/ sec c) One meter/sec d) One second/m

14. What is the speed of a 150Hz wave having wavelength 0.30m a) 45m/s b) 500m/s c) 0.0020m/s d) None

15. A source produces 50 crests and 50 troughs in 0.5 sec. What is the frequency of the wave? a) 100Hz b) 150Hz c) 50Hz d) 125Hz

16. Velocity of sound is maximum in a) Air b) Vacuum c) Water d) Metal

17. The Ratio of the speed of a body to speed of sound is called a) Sonic index b) Doppler ratio c) Mach Number d) Refractive index

18. Which of the following statements is wrong a) Sound travels in straight line b) Sound is form of energy c) Sound travels in the form of waves d) Sound travels faster in vacuum than in air

19. Voice of an individual is recognized by its a) intensity b) Pitch c) Timber d) velocity

20. The velocity of sound is affected by change in a) pressure b) wavelength c) medium d) temperature

21. Which of the following statements are correct? a) Pitch of sound depends on its frequency b) Loudness of sounds depends on its intensity c) Sound travels faster in air than in solids d) Speed of sound varies in air with temperature

22. Which of the following is an example of electromagnetic wave a) X- ray b) Water waves c) Wave produced on a stretched spring d) None

23. When a longitudinal wave propagate through a medium which quantities are transmitted in the direction of propagation a) energy , momentum and mass b) energy and mass c) Energy d) energy and linear momentum

24. A man stands between two cliffs , when he blows a whistle he hears firs echo after 0.4 s and second echo after 1.2 s. What is the distance between cliffs? a) 166m b) 66m c) 264m d) 300m

25. In along spring which of the following waves can be generated a) Longitudinal waves b) Transverse waves c) electromagnetic waves d) A & B

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