# NCERT solutions for Science Exemplar Class 8 chapter 13 - Sound [Latest edition]

## Chapter 13: Sound

Multiple Choice Questions [Pages 73 - 74]

### NCERT solutions for Science Exemplar Class 8 Chapter 13 Sound Multiple Choice Questions [Pages 73 - 74]

Multiple Choice Questions | Q 1. | Page 73

A list of mediums is given below

1. Wood
2. Water
3. Air
4. Vacuum

In which of these mediums can sound travel?

• i & ii only

• i, ii & iii only

• iii & iv only

• ii, iii & iv only

Multiple Choice Questions | Q 2. | Page 73

The loudness of sound depends on

• its amplitude

• its time period

• its frequency

• its speed

Multiple Choice Questions | Q 3. | Page 73

Which of the following statements are correct?

1. Sound is produced by vibrations.
2. Sound requires a medium for propagation.
3. Light and sound both require a medium for propagation.
4. Sound travels slower than light.
• i & ii only

• i, ii & iii only

• ii, iii & iv only

• i, ii, iv only

Multiple Choice Questions | Q 4. | Page 73

An object is vibrating at 50 Hz. What is its time period?

• 0.02 s

• 2 s

• 0.2 s

• 20.0 s

Multiple Choice Questions | Q 5. | Page 73

In order to reduce the loudness of a sound, we have to

• decrease its frequency of vibration of the sound

• increase its frequency of vibration of the sound

• decrease its amplitude of vibration of the sound

• increase its amplitude of vibration of the sound

Multiple Choice Questions | Q 6. | Page 73

Loudness of sound is measured in units of

• decibel (dB)

• metre (m)

• hertz (Hz)

• metre/second (m/s)

Multiple Choice Questions | Q 7. | Page 74

The loudness of sound is determined by its

• amplitude of vibration

• ratio of amplitude and frequency of vibration

• frequency of vibration

• product of amplitude and frequency of vibration

Multiple Choice Questions | Q 8. | Page 74

1 hertz is equal to

• 1 vibration per minute

• 10 vibrations per minute

• 60 vibrations per minute

• 600 vibrations per minute

Multiple Choice Questions | Q 9. | Page 74

Pitch of sound is determined by its

• frequency

• speed

• amplitude

• loudness

Multiple Choice Questions | Q 10. | Page 74

Ultrasound has frequency of vibration

• between 20 and 20000 Hz

• below 20 Hz

• above 20000 Hz

• between 500 and 10000 Hz

Very Short Answer Questions [Page 74]

### NCERT solutions for Science Exemplar Class 8 Chapter 13 Sound Very Short Answer Questions [Page 74]

Very Short Answer Questions | Q 11. | Page 74

Lightning can be seen at the moment when it occurs. Paheli observes lightning in her area. She hears the sound 5 s after she observed lightning. How far is she from the place where lightning occurs?

(speed of sound = 330 m/s).

Very Short Answer Questions | Q 12. | Page 74

Does any part of our body vibrate when we speak? Name the part.

Very Short Answer Questions | Q 13. | Page 74

Boojho saw a cracker burst at night at a distance from his house. He heard the sound of the cracker a little later after seeing the cracker burst. Give reason for the delay in hearing the sound.

Very Short Answer Questions | Q 14. | Page 74

When we hear a sound, does any part of our body vibrate? Name the part.

Very Short Answer Questions | Q 15. | Page 74

Name two musical instruments which produce sound by vibrating strings.

### NCERT solutions for Science Exemplar Class 8 Chapter 13 Sound Short Answer Questions [Page 75]

Short Answer Questions | Q 16. | Page 75

A simple pendulum makes 10 oscillations in 20 s. What is the time period and frequency of its oscillations?

Short Answer Questions | Q 17. | Page 75

We have learnt that vibration is necessary for producing sound. Explain why the sound produced by every vibrating body cannot be heard by us?

Short Answer Questions | Q 18. | Page 75

Suppose a stick is struck against a frying pan in vacuum. Will the frying pan vibrate? Will we be able to hear the sound? Explain.

Short Answer Questions | Q 19. | Page 75

Two astronauts are floating close to each other in space. Can they talk to
each other without using any special device? Give reasons.

Short Answer Questions | Q 20. | Page 75

List three sources of noise pollution in your locality.

### NCERT solutions for Science Exemplar Class 8 Chapter 13 Sound Long Answer Questions [Page 75]

Long Answer Questions | Q 21. | Page 75

We have a stringed musical instrument. The string is plucked in the middle first with a force of greater magnitude and then with a force of smaller magnitude. In which case would the instrument produce a louder sound?

Long Answer Questions | Q 22. | Page 75

How is sound produced and how is it transmitted and heard by us?

Long Answer Questions | Q 23. | Page 75

An alarm bell is kept inside a vessel as shown in figure. A person standing close to it can distinctly hear the sound of alarm. Now, if the air inside the vessel is removed completely, how will the loudness of alarm get affected for the same person?

Long Answer Questions | Q 24. | Page 76

The town hall building is situated close to Boojho’s house. There is a clock on the top of the townhall building which rings the bell every hour. Boojho has noticed that the sound of the clock appears to be much clearer at night. Explain.

Long Answer Questions | Q 25. | Page 75

Suggest three measures to limit noise pollution in your locality.

## NCERT solutions for Science Exemplar Class 8 chapter 13 - Sound

NCERT solutions for Science Exemplar Class 8 chapter 13 (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 CBSE Science Exemplar Class 8 solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. NCERT textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Science Exemplar Class 8 chapter 13 Sound are Properties of Sounds, Noise and Music, Noise Pollution, Sound Produced by Humans, Propagation of Sound, Human Ear, Sound, Production of Sound, Musical Instruments, Sound Need a Medium to Travel, Characteristics of a Sound Wave, Oscillator, Oscillation and Oscillatory Motion, Loudness and Intensity, Pitch (or shrillness) and frequency, Audibility and Range.

Using NCERT Class 8 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 NCERT Solutions are important questions that can be asked in the final exam. Maximum students of CBSE Class 8 prefer NCERT Textbook Solutions to score more in exam.

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