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

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 30 ⁰ C 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:

Subjective Problems :

1. 17m, 17mm
2. 780.8 m