Telangana SCERT Class 9 Physical Science Chapter 12 Sound Solution

Telangana SCERT Class 9 Physical Science Chapter 12 Solution – Sound. Here in this post we provides Class 9 Physical Science Sound Telangana State Board Solution. Telangana State Board English Class IX Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.

Telangana State Board Class 9 Physical Science Chapter 12 Sound Solution:





Reflections on concepts

1)Explain the following terms

a) amplitude b) wavelength c) frequency (AS1).

Ans: – Amplitude: – The maximum oscillation of any oscillator or wave is known as the amplitude.

Wavelength: – The distance between two successive crests in any oscillator or wave is known as the wavelength.

Frequency: –  The rate per second of the vibration of a oscillation is known as frequency.

2)Write the relation between wavelength, frequency and speed of sound (AS1)

Ans: – The relation between them is, v=ny.

Where v=speed of sound, n=frequency, y=wavelength.

3)Which has larger frequency – infrasonic sound or ultrasonic sound? (AS2)

Ans: – The ultrasonic sound has frequency is more than 20Kz which is greater than infrasonic.

4)Why is soft furnishing avoided in concert halls? (AS7)

Ans: – The soft furnishing always be avoided in a concert hallfor getting the best quality of sound. As if there are soft furnishings in concert hall then there will be multiple reflection of sound will be seen and this crate the disruption of main sound wave.


Application of concepts

1) Does the sound follow same laws of reflection as light does? (AS1)

Ans: – The sound wave follows the same law as the light follows the reflection law. In this like the light different sound wave fallen in a same plan and incidence and reflected rays are fallen and move out in same angle.

2) Two sources A and B vibrate with the same amplitude. They produce sounds of frequencies 1kHz and 30kHz respectively. Which of the two waves will have larger power? (AS1)

Ans: – The sound frequency is directly proportional to the speed of light so from this condition we can clearly say that the sound wave maximum value has more power as compared to the other wave which has smaller value.

4)How are multiple reflections of sound helpful to doctors and engineers?

Ans: – The sound wave has a property of multiple reflection which helps in the medical as well as the engineering field as in medical field the doctor uses the stethoscopes for measuring the heart beat which heard by this by the principal of multiple reflection and in engineering field the houses of cinema hall are made in such. Way that the multiple reflection helps to hear the sound in higher value in that room.


Higher Order Thinking Questions

1) the working and applications of SONAR. (AS1)

Ans: – The SONAR is the method by which the submarine and the different warships in ocean predict the depth of ocean. In this system the ultrasonic sound wave are uses and there happened multiple reflection of sound which helps to find the depth.

2) How do echoes in a normal room affect the quality of the sounds that we hear?

Ans: – The echoes are nothing but the multiple reflection of sound wave which affect the sound quality. So, if echoes are hearing in room temperature, then we see that the sound which is hearing is different that the main sounds.



1.) When can you say that the sound is propagating through a medium

a) If the medium is travelling

b) The particles of a medium are travelling

c) When the source of sound is travelling

d) When the disturbance is travelling.

Ans: –option (b).

2.) The unit for the number of waves produced in a second are

a) hertz b) joule c) meter d) pascal.

Ans: – option (a).

3.) The sounds of frequency less than 20 Hz are known as

a) Audible range b) Ultra sounds c) Infra sounds d) Sonic boom.

Ans: – option (c).

4.) The sound limit between the frequency of 20Hz – 20000Hz is called as

a) Audible range b) Ultra sound range c) Infra sound range d) Sonic boom.

Ans: – option (b).

Updated: January 27, 2022 — 11:05 am

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