# Sound Reflection

PhysicsSound

#### Class 11th Physics - Elasticity

6 Lectures 1 hours

#### Class 11th Physics - Oscillations

12 Lectures 2 hours

#### Class 11th Physics - Waves

14 Lectures 3 hours

## Introduction

Sound wave reflection at the barrier as if from the source of imagination at a similar distance behind the obstruction.

Sound reflection provides rise to reverberation, echo and diffusion. Distinct surfaces possess distinct powers of reflection as calculated by the reflection coefficient or absorption coefficient. Concave surfaces centre on the waves of sound thereby focusing the sound in particular areas and convex surfaces or shapes generally disperse the sound by fostering good diffusion. It is demonstrated that symmetrically drawn surfaces create symmetrical reflections, as the most prominent instance is the whispering gallery. This sound travels along the cliffs through a parabolic reflector and repeated reflections where all the reflection of sound focuses on the parabola.

Sound is demonstrated as the auditory sensation or oscillations that are summoned by oscillations in the velocity or displacement of particles.

## What is Sound reflection?

Sound reflection is demonstrated irrespective of different surfaces if the waves of sound proceed to a similar medium and that sound wave bounces back in the backward direction either fully or partially. Human beings in their daily lives are not able to interact verbally without sound waves.

Figure 1: Sound reflection

• Sound waves happen as a consequence of the vibration of atoms from distinct sources and advance throughout the atmosphere.
• The vibration of sound makes the wave of energy and is also used for interaction to act on different tasks (Mi et al. 2021).
• Sound waves also portray the reflection law. Sound waves proceed through the IT stage and transform when reflected from the boundary of the deeper medium. Hence, the incident wave's compression is backed as a compression.

## Laws of reflection of sound

Sound reflection follows the laws of reflection like the reflection of light. The sound heard after the deliberation from the tough surface is called echo making a sound persistent even after the sound source has prevented vibrating (Tsunokuni, Ikeda & Osaka, 2021). In case the sound is not transferred or absorbed when it hits the plane, it gets reflected. The two laws of reflection of sound are

• The incidence angle of the sound wave equals the reflection angle.

• The normal sound, incident sound and refractor sound'' lie in a similar plane.

Figure 2: Reflection

The laws of reflection of sound waves are just as in the case, the reflections were created by the stimulus' mirror image on the surface's opposite side. The reflection law holds when the sound's wavelength is different from the reflecting surface's dimensions.

## Application of Sound reflection

Several applications of Sound reflection are mentioned below:

Echo: Humans can have the Sound reflection with constant vibrations if the sound advances from a tough surface. The echo can be produced through a wall or a cliff which is the major instance of Sound reflection (Fu, Cao & Xu, 2019). Ranging techniques, sound navigation and SONAR utilise the principle of Sound reflection in navigating and detecting the materials available under the water. Dolphins and bats utilise these echoes to search out the barriers in the journey.

Soundboard: The soundboards are structured as curved-shaped concave boards. Soundboards are utilised for the audience's convenience present in the seminar hall or auditorium. Soundboards are generally placed contrasted to the speakers (Lisyutin, Yaroshenko & Lastovenko, 2020). The sounds take the signals of speakers utilising the loss of Sound reflection and reflect the similarities with more quality and precision to the audience (Gubaidullin & Gafiyatov, 2018). This assists the listener's potentiality for hearing with more clarity and precision even though they sit far away from speakers, mike or jukebox.

Figure 3: Reflection of sound in rooms

Megaphone: Sound reflection is an important instance of megaphones. The megaphones are similar to the tubes horn-shaped which assist in preventing the multiple reflection and Echoes while communicating verbally (Golovko, Ledenev & Antonov, 2019). In this context, all the sound waves are tuned and finely tuned into a tube. The megaphones are widely used to create distinct announcements.

Stethoscope: It is the most needed diagnostic equipment of the doctor. The doctors hear the moment of an organ or anything happening within the body of a human. The stethoscope also works on Sound reflection’s principle (Gubaidullin & Gafiyatov, 2018). The sound captured from the chest is heard by doctors with the assistance of the tube and it is regarded as the most important and basic tool for doctors.

## Conclusion

Sound is propagated in a particular medium with the internal force. Propagation of sound is reflected as a mechanical wave through a transparent medium such as water or air. Reflection of sound is defined as the sound heard when deliberations happen from the base surface and an instance is a cliff or wall. Sound is extremely important in day-to-day life without which interaction with the outer world is not possible. Similar to Sound reflection, sound energy is concerned with the vibration of sound waves. Sound does not have the capability of passing through the vacuum and sound waves cannot be visible. The phenomenon of bouncing back waves from the plane is called the reflection of sound.

## FAQs

Q1. What is the sound intensity?

The sound intensity is illustrated as the energy amount proceeding through the unit area at a certain point. Sound intensity is inversely proportional to the distance squared between the source and the point. Sound intensity is directly comparable to the square of frequency and vibration to the medium density.

Q2. How is a sound created?

Movement happens in the surrounded air molecules when any sort of object vibrates. The molecules often bump the molecules that are closest letting them vibrate. The movement of a chain reaction is referred to as sound waves which keep continuing until the molecules go out of focus and energy.

Q3. Which materials or objects reflect most of the sound?

Metal surfaces on average tend to reflect the highest percentage of the original sound input. In many cases, wood has the probability of continuously reflecting a small sound amount.

Q4.What is reverberation?

Reverberations are utilised to illustrate the principle of Sound reflection. It can be distinguished from distinct applications because it helps in explaining the will of sound persistence which is seen after several reflections. The reflected sound may be of poor quality or blurred due to several reflections for a long time.

## References

### Journals

Fu, Y., Cao, Y., & Xu, Y. (2019). Multifunctional reflection in acoustic metagratings with simplified design. Applied Physics Letters, 114(5), 053502. Retrieved from: https://aip.scitation.org

Golovko, A., Ledenev, V., & Antonov, A. (2019). The influence of the nature of Sound reflection from enclosures on the reverberation processes in the rooms. In MATEC Web of Conferences (Vol. 265, p. 05014). EDP Sciences. Retrieved from: https://www.matec-conferences.org

Gubaidullin, D. A., & Gafiyatov, R. N. (2018, July). Reflection and Transmission of Sound Waves through the Layer of Two-fractional Bubbly Liquid. In Journal of Physics: Conference Series (Vol. 1058, No. 1, p. 012055). IOP Publishing. Retrieved from: https://iopscience.iop.org

Lisyutin, V., Yaroshenko, A., & Lastovenko, O. (2020). Application of the extended poroacoustic model of marine sediments to the calculation of the Sound reflection coefficient from the seabed. In E3S Web of Conferences (Vol. 224, p. 02011). EDP Sciences. Retrieved from: https://www.e3s-conferences.org

Mi, Y., Zhai, W., Cheng, L., Xi, C., & Yu, X. (2021). Wave trapping by acoustic black hole: Simultaneous reduction of Sound reflection and transmission. Applied Physics Letters, 118(11), 114101. Retrieved from: https://aip.scitation.org

Tsunokuni, I., Ikeda, Y., & Osaka, N. (2021, March). Sound field visualization for primary reflection using equivalent sources and image source methods. In International Workshop on Advanced Imaging Technology (IWAIT) 2021 (Vol. 11766, pp. 90-95). SPIE. Retrieved from: https://www.spiedigitallibrary.org

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