CBSE Class 9 - Science - CH 12 - Sound (Worksheet)

CBSE Class 9 - Science - CH 12 - Sound (Worksheet)

SOUND

Worksheet

RADAR works on which principle?

Fill in the blanks

1. When we hear music, the medium through which the sound transmitted is __________ (solid, liquid, gas)

2. If a body repeats its motion, within fix interval of time, along a certain path, about a fixed point, it is said to have ____________.

3. A ________ (pulse/wave) is a form of disturbance which travels through a medium as a result of repetitive oscillations of the particles of the medium.

4. A ________ (pulse/wave) is a disturbance which is sudden and lasts for a short duration of time.

5. If a body repeats its back and forth, to and fro or up and down motion along a certain path, about a fixed point, in a certain time interval then the motion of such objects is said to be _____________.

6.  Number of oscillations completed by the oscillator in one second is known as ___________.

7. Waves which require a material medium for propagation are called _____________ waves. Example of such waves is _________. Light waves are ___________, because they can travel in vacuum.

8. The principle on which stethoscope works is _____ (reflection/ multiple reflection)

9. Sound travels as successive ____________ and _____________ in the medium.

10. Waves transport _________ not matter.

11.  In a __________ wave the particles of the medium oscillate in a direction perpendicular to the direction in which the wave propagates. 

12. Ripples waves on water surface are example of  ____________.

13. In a  _____________ wave the particles of the medium oscillate in the direction in which the wave travels.

14. Sound, compressional waves in springs are examples of _____________.

15.  In the case of ____________ wave, distance between two consecutive crests or troughs is known as wavelength.

16. In the case of a ___________ wave, distance between two consecutive condensations or rarefactions is known as wavelength.

17. RADAR (Radio Detection And Ranging) works on _____________ principle which is used to determine the velocities and movement of aircrafts.

18. Full form of SONAR is __________________________.

19. Audible sound range is  _________ to _____________. 

20. The product of wavelength of wave and its frequency gives _____________.

21. Sound having frequency less than 20Hz is known as ___________.

22. Sound having frequency more than 20,000Hz is known as ___________.

23. The distance between two consecutive compressions or two consecutive rarefactions is called the ______________.

24. Existence of sound waves in an auditorium due to multiple reflections suffered by the walls and ceiling is called ____________.

25. If the time interval between original sound and reflected sound is more than 1/10 second then original sound and reflected sound can be heard clearly. This reflected sound is known as _______.

26. v = ? × ?

27. Loudness of sound is measured in ___________.

Answers:

1. gas

2. periodic motion

3. wave

4. pulse

5. oscillatory

6. frequency

7. mechanical waves, sound. electromagnetic waves

8. multiple reflection

9. compressions, rarefactions

10. energy

11. transverse

12. transverse waves

13. longitudinal

14. longitudinal waves

15. transverse

16. longitudinal 

17. Doppler effect 

18. Sound Navigation and Ranging

19. 20Hz to 20,000Hz

20. wave velocity

21. infrasonic sound or infrasonics

22. ultrasonic sound

23. wavelength,

24. reverberation
25. echo
26.  v = ν × λ
27. decibel (db)