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# Selina solutions for Class 7 Physics chapter 6 - Sound

## Chapter 6: Sound

#### Selina solutions for Class 7 Physics Chapter 6 [Page 0]

Write true or false .

Sound can travel in vacuum.

Write true or false .

Sound is a form of energy.

Write true or false .

Sound can only be produced by vibrating bodies.

Write true or false .

Larger is the amplitude, feeble is the sound.

Write true or false .

The frequency is measured in hertz.

Write true or false .

Loudness depends on frequency.

Write true or false.

Waveforms of two different stringed instruments can be the same.

Write true or false .

Female voice is shriller than the male voice.

Write true or false.

A ticking clock sound is heard late when heard through a metal.

Fill in the blank.

Sound is produced when a body ...............

Fill in the blank.

The number of times a body vibrates in one second is called its.........................

Fill in the blank.

The pitch of a sound depends on its ...................

Fill in the blank.

Sound can travel in a .......................................

Fill in the blank.

We can hear sounds of frequency in the range of .......................

Fill in the blank.

Sound requires a .............. for propagation.

Fill in the blank.

Sound travels faster in ............. than in liquids.

Fill in the blank.

The sound heard after reflection is ........

Fill in the blank.

..............produces sensation in ears.

 Column A Column B (a) Vibrations cause (1) absorb sound (b) A shriller sound is (2) second (c) Unit of frequency (3) sound (d) Unit of time period (4) of high pitch (e) Curtains (5) hertz

Select the correct alternative :

We can distinguish a shrill sound from a flat sound by its

1.  amplitude
2.  loudness
3.  pitch
4.  none of the above.

Select the correct alternative :

We can hear sound of frequency

1.  10 Hz
2.  500 Hz
3.  100,000 Hz
4.  50,000 Hz

Select the correct alternative :

Sound cannot travel in

1.  gases
2.  liquids
3.  solids
4.  vacuum

Select the correct alternative:

The minimum distance required between the source and the reflector so as to hear the echo in air is

1.  10m
2. 17m
3.  34 m
4.  50 m

Select the correct alternative :

Wavelength is measured in

1.  kg
2.  second
3.  litre
4. metre

Select the correct alternative :

The speed of sound in water is

1.  332 m
2. 1500 m
3.  5000 m s
4.  1000 m s

Select the correct alternative :

Sound travels the fastest in

1.  liquids
2.  solids
3.  gases
4.  vacuum

#### Selina solutions for Class 7 Physics Chapter 6 [Page 0]

What do you mean by a vibratory motion ?

What is sound ?

How is sound produced ?

Describe an experiment to show that each source of sound is a vibrating body.

Name two sources of sound.

How do we produce sound ?

The bees do not have voice-boxes. How do they produce sound ?

Can sound travel through a vacuum ? Describe an experiment to explain your answer.

Describe an experiment to show that sound can travel in water.

Describe an experiment to show that sound can travel in a solid.

Can two person hear each other on moon’s surface ? Give reason to support your answer.

What is a longitudinal wave ?

Define Amplitude ?

Define Frequency?

Define time period ?

Write the audible range of frequency for the normal human ear.

What are ultrasonics ? Can you hear the ultrasonic sound ?

What are infrasonics ? Can you hear them ?

How does a bat make use of ultrasonics waves to find its way?

Name the two characteristics of sound which differentiate two sounds from each other.

On what factor does the loudness of a sound depend ?

How does the loudness of sound produced depend on the vibrating area of the body ?

The outer case of the bell in a temple is made big. Give a reason.

State the factors on which the pitch of a sound depends.

Differentiate between a high pitch sound and a low pitch sound.

How does a man’s voice differ from a woman’s voice ?

Name the characteristic which differentiates two sounds of the same pitch and same loudness.

You recognize your friend by hearing his voice on a telephone. Explain.

A musician recognizes the musical instrument by hearing the sound produced by it, even without seeing the instrument. Which characteristic of sound makes this possible ?

Describe an experiment to show the production of sound having low and high pitch.

How does a musician playing on a flute change the pitch of sound produced by it ?

Why are musical instruments provided with more than one string ?

How can the pitch of sound produced in a piano be changed ?

Explain why you can predict the arrival of a train by placing your ear on the rails without seeing it.

Write the approximate speed of sound in air.

Write the approximate speed of sound in water .

Write the approximate speed of sound in steel.

During a thunderstorm, the sound of a thunder is heard after the lightning is seen. Why ?

Describe an experiment to estimate the speed of sound in air.

Can sound travel through solids and liquids ? In which of these two does it travel faster ?

What do you mean by reflection of sound ?

State one use of reflection of sound.

What is echo ?

What minimum distance is required between the source of sound and the reflecting surface to hear an echo ? Give reason.

List four substances which are good absorbers of sound.

List the measures that you will take when designing a sound-proof room.

#### Selina solutions for Class 7 Physics Chapter 6 [Page 0]

A boy fires a gun and another boy at a distance of 1020 m hears the sound of firing the gun 3 s after seeing its smoke. Find the speed of sound.

A boy on a hill A fires a gun. The other boy on hill B hears the sound after 4 s. If the speed of sound is 330 m s-1, find the distance between the two hills.

## Selina solutions for Class 7 Physics chapter 6 - Sound

Selina solutions for Class 7 Physics chapter 6 (Sound) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Selina Concise Physics - Middle School for Class 7 solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Class 7 Physics chapter 6 Sound are Sources of Sound, Sound as a Longitudinal Wave, Characteristics of a Sound Wave: Amplitude (Relate Amplitude with Loudness), Characteristics of a Sound Wave - Frequency, Sound Needs a Medium to Propagate, Reflection and Absorption of Sound, Relative Speed of Sound in Different Mediums, Concept of Sound.

Using Selina Class 7 solutions Sound exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 7 prefer Selina Textbook Solutions to score more in exam.

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