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Have you wondered how fast sound travels, how we measure the loudness of sound and what makes a melody sound good? Explore the fun side of science with Class 9 NCERT Sound Solutions – where you learn how sound travels in a super easy way! The chapter will teach you about the important parameters required to study sound such as loudness and pitch, and how they relate to sound waves.
These expert answers help you get ready for competitive examinations while making tough concepts simple to understand. The NCERT Exemplar Solutions for Class 9 Science Chapter 12 – Sound lets students understand how sound is being produced and the various factors involved. These solutions are specially made by experts at Careers360 for students who are preparing for competitive exams like JEE Main or NEET. These solutions make the concepts easy to learn and grasp for students.
Question:1
Note is a sound
(a) of mixture of several frequencies
(b) of mixture of two frequencies only
(c) of a single frequency
(d) Always unpleasant to listen
Question:2
A key of a mechanical piano struck gently and then struck again but much harder this time. In the second case
(a) sound will be louder but pitch will not be different
(b) sound will be louder and pitch will also be higher
(c) sound will be louder but pitch will be lower
(d) both loudness and pitch will remain unaffected
Question:3
In SONAR, we use
(a) ultrasonic waves
(b) infrasonic waves
(c) radio waves
(d) audible sound waves
Question:4
Sound travels in air if
(a) Particles of medium travel from one place to another
(b) There is no moisture in the atmosphere
(c) Disturbance moves
(d) Both particles as well as disturbance travel from one place to another.
Answer:
Answer: CQuestion:5
When we change feeble sound to loud sound we increase its
(a) frequency
(b) amplitude
(c) velocity
(d) wavelength
Answer:
Answer: BQuestion:6
In the curve (Fig.12.1) half the wavelength is
(a) A B
(b) B D
(c) D E
(d) A E
Answer:
Answer: BQuestion:7
Earthquake produces which kind of sound before the main shock wave begins
(a) ultrasound
(b) infrasound
(c) audible sound
(d) none of the above
Answer:
Answer: BQuestion:8
Infra sound can be heard by
(a) dog
(b) bat
(c) rhinoceros
(d) human beings
Answer:
Answer: CQuestion:9
Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the string suitably. By doing so, he is adjusting:
(a) intensity of sound only
(b) amplitude of sound only
(c) frequency of the sitar string with the frequency of other musical instruments
(d) loudness of sound
Answer:
Answer: CQuestion:10
Answer:
In propagation of sound, the particle of medium oscillates.Question:11
Answer:
The difference between human male voice and female voice is on the basis of pitch or frequency.Question:12
Answer:
When we observe a sound directly or after reflection from any building, we call it an echo.Question:13
Answer:
The human ear can sense sound only if its frequency is more than 20 Hz and less than 20,000 Hz.Question:14
Answer:
Transverse wave cannot travel in air or within the water.Question:15
Answer:
The speed of light is very large in comparison with the speed of sound.Question:16
For hearing the loudest ticking sound heard by the ear, find the angle x in the Fig.12.4.
Answer:
Similar to light, sound also follows law of reflection.Question:17
Why is the ceiling and wall behind the stage of good conference halls or concert halls made curved?
Answer:
The design of ceiling and wall in a good conference hall is to ensure proper sound at every seat of the conference hall.Question:18
Represent graphically by two separate diagrams in each case
(a) Two sound waves having the same amplitude but different frequencies?
(b) Two sound waves having the same frequency but different amplitudes.
(c) Two sound waves having different amplitudes and also different wavelengths.
Answer:
In propagation of sound, the particle of medium oscillates.Question:19
Establish the relationship between speed of sound, its wavelength and frequency. If velocity of sound in air is 340 m s–1, calculate
(i) Wavelength when frequency is 256 Hz.
(ii) Frequency when wavelength is 0.85 m.
Answer:
The wavelength of any sound is defined as distance travelled by disturbance in one time period of the oscillation of particle.Question:20
Answer:
In propagation of sound, the particle of medium oscillate.Topics covered in the chapter via Class 9 Science NCERT Exemplar Chapter 12 solution are:
Chapter wise solutions |
These Class 9 Science NCERT Exemplar Chapter 12 solutions explain the basics of sound and how it travels.
They are very useful for higher classes and exams like JEE and NEET.
You can use these solutions to practice and understand the topic clearly.
They are enough to help you prepare for other books too, like the NCERT textbook or S. Chand.
Check NCERT Solutions for questions given in the book
Chapter No. | Chapter Name |
Chapter 1 | Matter in Our Surroundings |
Chapter 2 | Is Matter Around Us Pure |
Chapter 3 | Atoms and Molecules |
Chapter 4 | Structure of The Atom |
Chapter 5 | The Fundamental Unit of Life |
Chapter 6 | Tissues |
Chapter 7 | Diversity in Living Organisms |
Chapter 8 | Motion |
Chapter 9 | Force and Laws of Motion |
Chapter 10 | Gravitation |
Chapter 11 | Work and Energy |
Chapter 12 | Sound |
Chapter 13 | Why Do We Fall ill? |
Chapter 14 | Natural Resources |
Chapter 15 | Improvement in Food Resources |
When sound travels and changes medium, the speed of sound changes. It causes a change in wavelength but not the frequency. Frequency does not depend on the medium.
No, the frequency of sound produced by any woman does not change on changing the loudness. The intensity of sound increases on shouting but the frequency of sound will remain the same. Frequency is generally known as pitch which can be seen as identification of someone’s voice
No, sound needs medium to travel and there is no atmosphere on the moon. Therefore, we cannot talk on the moon as we talk on earth.
Yes! These are perfect for quick and smart revision before your tests.
Yes! They help you understand the chapter better and are great for exam practice.
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