CBSE Worksheet for chapter-9 Wave Motion & Sound class 9

Worksheet For class 9

Find CBSE Worksheet for chapter-9 Wave Motion & Sound class 9

CLASS-9

BOARD: CBSE

Physics Worksheet - 9

TOPIC: Wave Motion & Sound

For other CBSE Worksheet for class 9 Science check out main page of Physics Wallah.

SUMMARY

  • Wave motion, Classification of waves depending on medium & its direction of vibration
  • Sound wave, Production of sound waves, Propagation of sound.
  • Wave terminology, Range of hearing, Sonic boom.
  • Reflection of sound, Speed of sound in different medium, Effect of temperature on speed of sound, Echo, Reverberation
  • Audible, Ultrasonic and Infrasonic waves, Applications of ultrasound
  • Sonar – Principle and working of sonar, The human ear

SECTION I – OBJECTIVE

  1. What is velocity of sound in water at room temperature?
    1. 1500 m/s
    2. 330 m/s
    3. 1500 km/s
    4. 330 km/s
  2. Pitch of high frequency sound is:
    1. High
    2. Low
    3. Zero
    4. Infinity
  3. Voice of a friend is recognised by its:
    1. Pitch
    2. Quality
    3. Intensity
    4. Velocity
  4. A sonar echo takes 4.4sec to return from a submarine. If the speed of sound in water is 1500m/s, then the distance of submarine from the sonar is:
    1. 1500m
    2. 3000m
    3. 3300m
    4. 3600m
  5. When sound waves travelling in air enter into the medium of water, the quantity which remains unchanged is:
    1. Wavelength
    2. Velocity
    3. Frequency
    4. None
  6. The velocity of sound in air at 300C is approximately:
    1. 332 m/s
    2. 350 m/s
    3. 530 m/s
    4. 332 km/s
  7. Velocity of sound is maximum in
    1. Iron
    2. Mercury
    3. Water
    4. Air
  8. The sound propagates in a gaseous medium by:
    1. Transverse waves
    2. Longitudinal waves
    3. Both A and B
    4. Neither A nor B
  9. The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?
    1. 100
    2. 1000
    3. 600
    4. 6000
  10. Sound waves of wavelength ‘X’ travels from a medium in which their speed is V into a medium in which their speed is 4 V. The wavelength of sound in the second medium is:
    1. X
    2. 2X
    3. 3X
    4. 4X

SECTION II - SUBJECTIVE

  1. Define the following terms related to sound waves:
    1. Pitch
    2. Loudness
    3. Intensity
    4. Quality
  2. Distinguish between:
    1. Mechanical wave & Non mechanical wave
    2. Transverse wave &longitudinal wave
  3. Define reverberation.
  4. With the help of a suitable diagram explain the working of human ear.
  5. Define the following:
    1. Wave motion
    2. Amplitude
    3. Wavelength
    4. Ultrasound.
  6. Write any three applications of ultra sound.
  7. A person has a hearing range from 20Hz to 20Khz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies?(Speed of sound in air = 340m/s)
  8. A submarine emits a sonar pulse which returns from the underwater cliff in 1.02 sec. If the speed of sound in salt water is 1531m/s, how far away is the cliff?

Solutions: to worksheet-9 Wave Motion & Sound

Objective Problems:

1.(A) 2.(A) 3.(B) 4.(C) 5.(C) 6.(B) 7.(A) 8.(B) 9.(D) 10.(D)

Subjective Problems :

  1. 17m, 17mm
  2. 780.8 m

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