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![Selina solutions for Concise Physics [English] Class 9 ICSE chapter 8 - Propagation of Sound Waves - Shaalaa.com](/images/concise-physics-english-class-9-icse_6:8a0c4572dea049a29e575abe2d9ca662.jpg "Selina solutions for Concise Physics [English] Class 9 ICSE chapter 8 - Propagation of Sound Waves")
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Solutions for Chapter 8: Propagation of Sound Waves
Below listed, you can find solutions for Chapter 8 of CISCE Selina for Concise Physics [English] Class 9 ICSE.
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise 8 (A) [Pages 182 - 183]
What causes sound?
What is sound? How is it produced?
Complete the following sentence :
Sound is produced by a ___________ body.
Describe a simple experiment which demonstrates that the sound produced by a tuning fork is due to vibrations of its arms.
Describe in brief, with the aid of a lebelled diagram, an experiment to demonstrate that a material medium is necessary for propagation of sound.
There is no atmosphere on moon. Can you hear each other on the moon's surface?
State three characteristics of the medium required for propagation of sound?
Explain with an example, the propagation of sound in a medium.
Choose the correct word/words to complete the following sentence :
When sound travels in a medium ____________
the particles of the medium
the source
the disturbance
the medium
Name the two kinds of waves in form of which sound travels in a medium.
What is a longitudinal wave? In which medium: solid, liquid or gas, can it be produced?
What is a transverse wave? In which medium: solid, liquid or gas, can it be produced?
Explain meaning of the terms compression and rarefaction in relation to a longitudinal wave.
Explain the terms crest and trough in relation to a transverse wave.
Describe an experiment to show that in wave motion, only energy is transferred, but particles of medium do not move.
Define the term amplitude of a wave. Write its S.I. unit.
What do you mean by the term frequency of a wave? State its S.I. unit.
How is the frequency of a wave related to its time period?
Define the term wave velocity. Write its S.I. unit.
Draw displacement-time graph of a wave and show on it the amplitude and time period of wave.
Draw a displacement-distance graph of a wave and mark on it, the amplitude of wave by the letter 'a' and wavelength of wave by the letter λ.
How are the wave velocity V, frequency f and wavelength λ of a wave related? Derive the relationship.
State two properties of medium on which the speed of sound in it depends.
Arrange the speed of sound in gases Vg, solids Vs and liquids VLin an ascending order.
State the speed of (i) light and (ii) sound in air?
Compare approximately the speed of sound in air, water and steel.
Answer the following question :
Can sound travel in vacuum?
Answer the following question :
How does the speed of sound differ in different media?
Flash of lightning reaches earlier than the sound of thunder. Explain the reason.
If you place your ear close to an iron railing which is tapped some distance away, you hear the sound twice. Explain why?
The sound of an explosion on the surface of a lake is heard by a boat man 100 m away and by a diver 100 m below the point of explosion.
(i) Who would hear the sound first: boatman or diver?
(ii) Give a reason for your answer in part (i).
(iii) If sound takes time t to reach the boatman, how much time approximately does it take to reach the diver?
How does the following factor affect, if at all, the speed of sound in air:
Frequency of sound
How does the following factor affect, if at all, the speed of sound in air:
Temperature of air
How does the following factor affect, if at all, the speed of sound in air:
Pressure of air
How does the following factor affect, if at all, the speed of sound in air:
Moisture in air
How does the speed of sound change with change in (i) amplitude and (ii) wavelength, of sound wave?
In which medium the speed of sound is more: humid air or dry air? Give a reason to your answer.
How does the speed of sound in air vary with temperature?
Describe a simple experiment to determine the speed of sound in air. What approximation is made in the method described by you?
Complete the following sentences :
Sound cannot travel through __________, but it requires a ___________.
Complete the following sentences :
When sound travels in a medium, the particles of medium ___________ but the disturbance ___________.
Complete the following sentence :
A longitudinal wave is composed of compression and ____________.
Complete the following sentence :
A transverse wave is composed of crest and ____________.
Complete the following sentences :
Wave velocity = ________________ × wavelength.
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise 8 (A) [Page 183]
The correct statement is :
Sound and light both require medium for propagation.
Sound can travel in vacuum, but light can not
Sound needs medium, but light does not need medium for its propagation.
Sound and light both can travel in vacuum.
The speed of sound in air at 0°C is nearly :
1450 m s-1
450 m s-1
5100 m s-1
330 m s-1
Sound in air propagates in form of
Longitudinal wave
Transverse wave
Both longitudinal and transverse waves
Neither longitudinal nor transverse wave.
The speed of light in air is :
3 x 108 m s-1
330 m s-1
5100 m s-1
3 x 1010 m s-1
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise 8 (A) [Page 183]
The heart of a man beats 75 times a minute. What is its (a) frequency and (b) time period?
The time period of a simple pendulum is 2 s. Find its frequency.
The separation between two consecutive crests in a transverse wave is 100 m. If wave velocity is 20 m s-1, find the frequency of wave.
A longitudinal wave travels at a speed of 0.3 m s-1 and the frequency of wave is 20 Hz. Find the separation between two consecutive compressions.
A source of wave produces 40 crests and 40 troughs in 0.4 s. What is the frequency of the wave?
An observer A fires a gun and another observer B at a distance 1650 m away from A hears its sound. If the speed of sound is 330 m s-1, find the time when B will hear the sound after firing by A.
The time interval between a lightning flash and the first sound of thunder was found to be 5 s. If the speed of sound in air is 330 m s-1, find the distance of flash from the observer.
A boy fires a gun and another boy at a distance hears the sound of fire 2.5s after seeing the flash. If the speed of sound in air 340 m/s, find distance between the boys.
An observer sitting in line of two tanks watches the flashes of two tanks firing at each other at the same time, but he hears the sounds of two shots 2s and 3.5s after seeing the flashes. If distance between the two tanks is 510m, find the speed of sound.
How long will sound take to travel in (a) and iron rail and (b) air, both 3.3 km in length? Take speed of sound in air to be 330 m/s and in iron to be 5280 m/s.
Assuming the speed of sound in air equal to 340 m/s and in water equal to 1360 m/s, find the time taken to travel a distance 1700 m by sound in (i) air (ii) water.
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise 8 (B) [Page 185]
What do you mean by the audible range of frequency?
What is the audible range of frequency for human?
For which range of frequencies, human ears are most sensitive?
Which has the higher frequency - ultrasonic sound or infrasonic sound?
Complete the following sentences:
An average person can hear sound of frequencies in the range ______ to _________.
Complete the following sentence:
Ultrasound is of frequency ___________.
Complete the following sentence:
Infrasonic sound is of frequency ______________.
Complete the following sentence:
Bats can produce and hear ___________ sound.
Complete the following sentence:
Elephants produce ____________sound.
Name the sound of the frequency given below:
10 Hz
Name the sound of the frequency given below:
100 Hz
Name the sound of the frequency given below:
1000 Hz
Name the sound of the frequency given below:
40 kHz
Can you hear the sound produced due to vibrations of a seconds pendulum? Give reasons.
What is ultrasound?
State the approximate speed of ultrasound in air.
State two properties of ultrasound that make it useful to us.
Explain how do bats locate the obstacles and prey in their way.
State two applications of ultrasound.
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise 8 (C) [Page 185]
A man can hear the sound of frequency :
1 Hz
1000 Hz
200 kHz
5 MHz
The properties of ultrasound that make it useful are
High power and high speed
High power and good directivity
High frequency and high speed
High frequency and bending around the objects.
Sonar makes use of :
infrasonic sound
ultrasound
ordinary sound
light
Selina solutions for Concise Physics [English] Class 9 ICSE 8 Propagation of Sound Waves Exercise
Which wave property determines (a) loudness, (b) pitch?
What are wavelength, frequency, time period and amplitude of a sound wave?
Guess which sound has a higher pitch: guitar or car horn?
Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.
A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?
Distinguish between loudness and intensity of sound.
Which characteristics of the sound helps you to identify your friend by his voice while sitting with others in a dark room?
The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?
What is loudness of sound? What factors does it depend on?
Solutions for 8: Propagation of Sound Waves
Selina solutions for Concise Physics [English] Class 9 ICSE chapter 8 - Propagation of Sound Waves
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Concepts covered in Concise Physics [English] Class 9 ICSE chapter 8 Propagation of Sound Waves are Production of Sound, Propagation of Sound, Sound Need a Medium to Travel, Characteristics of a Sound Wave, Representation of a Wave, Relationship Between the Wavelength, Wave Velocity and Frequency, Factors Affecting Speed of Sound in Gas, Factors Not Affecting Speed of Sound in a Gas, Experimental Determination of Speed of Sound in Air, Properties of Sounds, Audibility and Range, Speed of Sound in Different Media, Speed of Sound (Velocity of Sound), Sound, Ultrasonic Sound Or Ultrasound, Difference Between the Sound and Light Waves.
Using Selina Concise Physics [English] Class 9 ICSE solutions Propagation of Sound Waves exercise by students is an easy way to prepare for the exams, as they involve solutions arranged chapter-wise and also page-wise. The questions involved in Selina Solutions are essential questions that can be asked in the final exam. Maximum CISCE Concise Physics [English] Class 9 ICSE students prefer Selina Textbook Solutions to score more in exams.
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