NCERT Solutions For Class 8 Science Chapter 10 Sound

Edited By Vishal kumar | Updated on Apr 21, 2025 01:02 PM IST

Whether it's the horn of a car, the chirping of birds, or the ringing of a cell phone, we hear various sounds every day. We constantly hear these sounds, but have you ever wondered how they are made? A steel bucket, for example, will vibrate when you tap it with a little hammer; these vibrations are what produce sound. Actually, the vibrations of objects are what make all sounds. Sound, Chapter 10 of Class 8 Science, goes into great detail on this concept.

This Story also Contains

NCERT Solutions for Class 8 Science Chapter 10 Sound
NCERT Solutions for Class 8 Science Chapter 10 Sound: Solved Exercise Questions
Sound Class 8 NCERT Science Chapter: Topics
NCERT Class 8 Physics Chapter 10 Exercise Solutions: Key Concepts and Formulas
NCERT Solutions for Class 8 Science Chapter 10 Sound: Points to Remember
NCERT Chapter-Wise Solutions For Class 8th Science

NCERT Solutions For Class 8 Science Chapter 10 Sound

Careers360 has updated the NCERT solutions for this chapter to help students in understanding these concepts. These solutions are presented in a clear manner and have been carefully prepared by experienced teachers. There are 13 questions in the chapter, including multiple-choice, fill-in-the-blank, true/false, and descriptive questions. Students' learning is greatly improved by the step-by-step explanation of each solution. These NCERT solutions are a reliable study tool for everything from exam preparation to homework problems.

Additionally, a downloadable PDF version is available so that students can revise even when offline.

As per the CBSE syllabus for the academic year 2025-26, this chapter has now been renumbered and is listed as Chapter 10.

NCERT Solutions for Class 8 Science Chapter 10 Sound

The chapter on Sound (Chapter 10, Class 8 Science) covers important concepts like how sound is produced, how it travels, and how we hear it. The solutions provided include a variety of questions and answers that help reinforce these ideas. They are especially useful for self-study, making it easier for students to understand key concepts and score well in exams.

NCERT Solutions for Class 8 Science Chapter 10 Sound: Solved Exercise Questions

Q1. Choose the correct answer.

Sound can travel through

(a) gases only (b) solids only (c) liquids only (d) solids, liquids and gases.

Answer:

Sound can travel through solids, liquids and gases. But the sound does not travel in a vacuum

(d) is correct.

Choose the correct answer.

Q2. Voice of which of the following is likely to have minimum frequency?

(a) Baby girl (b) Baby boy (c) A man (d) A woman

Answer:

Voice of a man would have the lowest frequency since it is of a lower pitch than the voice of a woman, a baby boy and a baby girl. Pitch is proportional to frequency.

Q3. In the following statements, tick ‘T’ against those which are true, and ‘F’ against those which are false.

(a) Sound cannot travel in vacuum. (T/F)
(b) The number of oscillations per second of a vibrating object is called its time period. (T/F)
(c) If the amplitude of vibration is large, sound is feeble. (T/F)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)
(e) The lower the frequency of vibration, the higher is the pitch. (T/F)
(f) Unwanted or unpleasant sound is termed as music. (T/F)
(g) Noise pollution may cause partial hearing impairment. (T/F)

Answer:

(a) T .

Sound cannot travel in a vacuum as it requires a medium to travel.

(b) F .

The number of oscillations per second of a vibrating object is called its frequency. Time period is the time taken to complete one oscillation.

The sound of a vibration is directly proportional to the square of the amplitude of vibration , therefore, the sound will be feeble if the amplitude of vibration is low.

(d) T .

For humans, the audible range of frequency is 20 Hz to 20,000 Hz.

(e) F .

The pitch of a sound is directly proportional to its frequency.

(f) F .

Unwanted or unpleasant sound is termed as noise.

(g) T .

Exposure to loud noise for a long period of time may cause partial hearing impairment.

4. Fill in the blanks with suitable words.

(a) Time taken by an object to complete one oscillation is called __________.
(b) Loudness is determined by the __________ of vibration.
(c) The unit of frequency is __________
(d) Unwanted sound is called __________ .
(e) Shrillness of a sound is determined by the __________ of vibration.

Answer:

(a) Time taken by an object to complete one oscillation is called time period .
(b) Loudness is determined by the amplitude of vibration.
(c) The unit of frequency is Hertz .
(d) Unwanted sound is called noise .
(e) Shrillness of a sound is determined by the frequency of vibration.

Q5. A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

Answer:

Time Period is defined as the time taken to complete one oscillation.

$Time taken to complete 40 oscillations = 4 secondsTime taken to complete 1 oscillation = \frac{4}{40} seconds = 0.1 second$

Frequency is defined as the number of oscillations per second.

$Number of oscillations in 4 seconds = 40 Number of oscillations in 1 second = \frac{40}{4} = 10 Frequency = 10 Hertz .$

Q6 . The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

Answer:

The time period of vibration is defined as the time taken to complete one oscillation.

$Time taken to complete 500 vibrations = 1 second. Time taken to complete 1 vibration = \frac{1}{500} second = 0.002 seconds. Time period = 0.002 seconds.$

Q7 . Identify the part which vibrates to produce sound in the following instruments.
(a) Dholak (b) Sitar (c) Flute

Answer:

(a) The stretched membrane over the body of the dholak vibrates to produce sound.

(b) The strings stretched over the body of the sitar vibrate to produce sound.

Q8 . What is the difference between noise and music? Can music become noise sometimes?

Answer:

Noise is sound which is irritating and unpleasant whereas music is sound which is pleasant and soothing. Music can turn into noise at very high volume.

Q9 . List sources of noise pollution in your surroundings.

Answer:

Sources of noise pollution in our surroundings are:

(a) Horns of vehicles on the road.

(b) Loudspeakers and radios.

(d) Machinery inside factories and appliances at homes.

(e) The noise produced by a large number of people.

Q10 . Explain in what way noise pollution is harmful to human.

Answer:

Noise pollution can cause several health-related problems such as:

(i) Insomnia.

(ii) Anxiety and stress.

(iii) Hearing impairment

(iv) Headaches.

Q11 . Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer.

Answer:

I would suggest them to buy the one three lanes away from the roadside as there will be less noise pollution caused by vehicles moving on the road.

Q12 . Sketch larynx and explain its function in your own words.

Answer:

1659074643577

Inside the larynx, there are two vocal cords with a gap between them and when air passes through this gap the vocal cords vibrate and as we know the sound is produced when something vibrates, therefore, this vibration of vocal cords inside the larynx produce sound.

Q13 . Lightning and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain why?

Answer:

The speed of light is much faster than the speed of sound, due to this the light emitted by lightning reaches our eyes before the sound of thunder reaches our ears and we see lightning before we hear thunder.

The Class 8 Science Chapter 10 (Sound) solutions include a total of thirteen questions, featuring a mix of multiple-choice questions, true/false statements, fill in the blanks, and subjective-type questions. Subject experts at Careers360 have prepared these answers in a simple and step-by-step format, making them easy to understand. A PDF version of the solutions is also available for download, allowing students to study at their own convenience.

Sound Class 8 NCERT Science Chapter: Topics

10.1 Sound is Produced by a Vibrating Body

10.2 Sound Produced by Humans

10.3 Sound Needs a Medium for Propagation

10.4 We Hear Sound through Our Ears

10.5 Amplitude, Time Period and Frequency of a Vibration

10.6 Audible and Inaudible Sounds

10.7 Noise and Music

10.8 Noise Pollution

NCERT Class 8 Physics Chapter 10 Exercise Solutions: Key Concepts and Formulas

1. Production of Sound

Sound is produced by vibrations of objects.
For example, plucking a rubber band or hitting a drum creates vibrations that produce sound.

2. Sound Produced by Humans

In humans, sound is produced by the voice box (larynx).
The voice box is located at the top of the windpipe.
It has two vocal cords with a slit in between. When air passes through, the cords vibrate and produce sound.

3. Propagation of Sound

Sound needs a medium (like air, water, or solid) to travel.
It cannot travel through a vacuum.
Sound travels fastest in solids, slower in liquids, and slowest in gases.

4. Frequency and Time Period

Frequency (f) is the number of vibrations per second.
- Unit: Hertz (Hz)
Time Period (T) is the time taken for one vibration.
- Formulas: f=1/T

5. Amplitude, Loudness, and Pitch

Amplitude is the height of the vibration wave. Greater amplitude = louder sound.
Loudness depends on amplitude and is measured in decibels (dB).
Pitch depends on frequency:
- High frequency = High pitch (e.g., a whistle)
- Low frequency = Low pitch (e.g., a drum)

6. Speed of Sound

Formula:
Speed of sound=Distance/Time
Speed varies in different media:
- It is the fastest in solids, slower in liquids, and slowest in gases.

NCERT Solutions for Class 8 Science Chapter 10 Sound: Points to Remember

Sound is produced by the vibrations of objects. Without vibration, no sound is created.
In humans, sound is produced by the voice box (larynx) located at the top of the windpipe.
Vocal cords inside the larynx vibrate to create sound when air passes through them.
Sound needs a medium (solid, liquid, or gas) to travel. It cannot travel through a vacuum.
The speed of sound is highest in solids, slower in liquids, and slowest in gases.
The amplitude of vibration affects the loudness of sound. Greater amplitude = louder sound.

NCERT Chapter-Wise Solutions For Class 8th Science

The chapter-wise NCERT solutions for all the science chapters are listed here along with their links:

NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe

NCERT Solutions for Class 8 Science Chapter 3 Coal and Petroleum

NCERT Solutions for Class 8 Science Chapter 4 Combustion and Flame

NCERT Solutions for Class 8 Science Chapter 5 Conservation of Plants and Animals

NCERT Solutions for Class 8 Science Chapter 6 Reproduction in Animals

NCERT Solutions for Class 8 Science Chapter 7 Reaching the Age of Adolescence

NCERT Solutions for Class 8 Science Chapter 8 Force and Pressure

NCERT Solutions for Class 8 Science Chapter 9 Friction

NCERT Solutions for Class 8 Science Chapter 10 Sound

NCERT Solutions for Class 8 Science Chapter 11 Chemical Effects of Electric Current

NCERT Solutions for Class 8 Science Chapter 12 Some Natural Phenomena

NCERT Solutions for Class 8 Science Chapter 13 Light

NCERT Solutions For Class 8: Subject-Wise

Also Check NCERT Books and NCERT Syllabus here:

Frequently Asked Questions (FAQs)

1. What is frequency?

Frequency is number of cycles per second. Frequency is measured in Hz. 1Hz=1/1 second

2. What produces sounds in human?

The vibration of vocal cords inside the larynx produce sound

3. What is the relation between pitch and frequency

Pitch is proportional to frequency.

Also Read

NCERT Solutions for Class 8 Maths Chapter 6 Cubes and Cube Roots

NCERT Solutions for Class 8 Science Chapter 3 Coal and Petroleum

NCERT Solutions for Class 8 Science Chapter 4 Combustion and Flame

NCERT Solutions for Class 8 Maths Chapter 2 Linear Equations in One Variable

NCERT Solutions for Class 8 Science Chapter 13 Light

NCERT Solutions for Class 8 Science Chapter 12 Some Natural Phenomena

NCERT Books for Class 8 Maths 2025-26: Download PDF Here

NCERT Books for Class 8 Social Science 2025-26 - Download PDF

NCERT Books for Class 8 Science 2025-26 PDF - Download Now

NCERT Books for Class 8 English 2025-26: Download PDF

NCERT Books for Class 8 2025-26: Download All Subjects PDF

NCERT Syllabus for Class 8 2025-26, Download All Subjects Latest Syllabus PDF

NCERT Syllabus for Class 8 Hindi 2025-26: Download All Chapters PDF Here

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