Sound Properties and Reflection
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Sound Properties and Reflection

This quiz covers the fundamentals of sound properties, including loudness and pitch, as well as sound reflection and transmission at interfaces between different media.

Created by
@IllustriousPlumTree

Questions and Answers

What is the frequency range of sound that humans can hear?

Roughly 20 Hz to 20 KHz

What is the primary factor that loudness of a sound depends on?

Intensity of the sound

What is the range of frequencies below 20 Hz called?

Infrasound

What happens when the acoustic impedance of two media are equal?

<p>Total transmission of the sound wave</p> Signup and view all the answers

What is one clinical application of ultrasound?

<p>Providing more information than an X-ray</p> Signup and view all the answers

What is the purpose of the bell in a stethoscope?

<p>To match the impedance between the body and the air in the tube</p> Signup and view all the answers

What is the unit of measurement for sound intensity?

<p>W/m²</p> Signup and view all the answers

What is the primary use of an audiogram?

<p>To detect hearing loss in individuals</p> Signup and view all the answers

What is the ratio of sound intensity to a reference intensity called?

<p>Intensity ratio</p> Signup and view all the answers

What is the effect of a large difference in acoustic impedance between two media?

<p>High reflection and low transmission</p> Signup and view all the answers

What characteristic of sound can the human ear distinguish?

<p>Two characteristics</p> Signup and view all the answers

What is the medical application of infrasound in the study of heart mechanical function?

<p>Seismocardiogram</p> Signup and view all the answers

What determines the natural frequency of a stethoscope bell?

<p>The diameter and tension of the diaphragm</p> Signup and view all the answers

What is the purpose of selecting a specific bell size and diaphragm tension in a stethoscope?

<p>To selectivity pick up certain frequency ranges</p> Signup and view all the answers

What is the purpose of measuring sound intensity?

<p>To compare it with a reference intensity</p> Signup and view all the answers

What is the term for the degree of sensation of sound produced in the ear?

<p>Loudness</p> Signup and view all the answers

What is the effect of intense infrasonic noise on the human body?

<p>Respiratory impairment and aural pain</p> Signup and view all the answers

What is the term for the measurement of the micro-vibrations produced by the heart contraction and blood ejection into the vascular tree?

<p>Seismocardiogram</p> Signup and view all the answers

What happens when there is a sign change in the reflected wave?

<p>There is a phase change in the reflected wave</p> Signup and view all the answers

What is the term for the ratio of reflected or transmitted waves to incident waves?

<p>Reflection coefficient</p> Signup and view all the answers

What is the term for the number of rarefactions and compressions that occur per unit time in a sound wave?

<p>Frequency</p> Signup and view all the answers

What is the speed of sound dependent on?

<p>Medium it propagates through</p> Signup and view all the answers

What is the definition of a sound wave?

<p>A pattern of disturbance caused by the energy traveling away from the source of the sound</p> Signup and view all the answers

What is the mathematical representation of the wavelength of a sound wave?

<p>λ = v/f</p> Signup and view all the answers

What is the term for the distance between successive compressions and rarefactions in a sound wave?

<p>Wavelength</p> Signup and view all the answers

How does the speed of sound change in different mediums?

<p>It increases in solids, decreases in liquids, and decreases in gases</p> Signup and view all the answers

What is the mathematical representation of the frequency of a sound wave?

<p>f = 1/T</p> Signup and view all the answers

What is the term for the energy transferred per unit time in a sound wave?

<p>Intensity</p> Signup and view all the answers

What is the relationship between frequency and wavelength of a sound wave?

<p>Frequency increases as wavelength decreases</p> Signup and view all the answers

What is the unit of measurement for the velocity of sound?

<p>Meters per second (m/s)</p> Signup and view all the answers

What is the primary characteristic of infrasound that allows it to travel long distances without losing much power?

<p>Low absorption and large wavelength</p> Signup and view all the answers

What is the primary difference between ultrasound and infrasound?

<p>Frequency range</p> Signup and view all the answers

What is the term for the study of heart mechanical function using infrasound?

<p>Seismocardiogram</p> Signup and view all the answers

What is the primary application of ultrasound in clinical medicine?

<p>Imaging of the fetus</p> Signup and view all the answers

What is the effect of intense infrasonic noise on the human body?

<p>Respiratory impairment and aural pain</p> Signup and view all the answers

What is the primary characteristic of a sound wave that allows it to transfer energy without transferring matter?

<p>Mechanical disturbance</p> Signup and view all the answers

What is the term for the local increase or decrease of pressure relative to atmospheric pressure in air?

<p>Compression</p> Signup and view all the answers

What is the primary reason why infrasound can travel through most media?

<p>Large wavelength</p> Signup and view all the answers

Study Notes

Characteristics of Sound

  • Loudness (or volume) is the degree of sensation of sound produced in the ear, dependent on its intensity.
  • Pitch refers to whether a sound is high (sharp) or low.

Sound Reflection and Transmission

  • When a sound wave is applied perpendicularly to the interface between two media with different acoustic impedance (Z1 and Z2), a portion of the wave passes through, and another portion is reflected.
  • The ratio of reflected (Iref) or transmitted (Itran) waves to the incident wave (Iin) can be measured.
  • If Z1 = Z2, there is no reflected wave, and transmission to the second medium is complete.
  • If Z2 < Z1, there is a phase change of the reflected wave.
  • If ∆Z is large, there is high reflection and low transmission (mismatching).

Audiogram

  • An audiogram for the normal human ear shows the faintest sounds that can be heard (hearing threshold) and the loudest sounds that can be heard without pain (pain threshold).
  • The sound of 1000Hz is barely audible.

Applications of Audible Sound in Medicine

  • Stethoscopes are diagnostic instruments that amplify sounds made by the body from the heart, lungs, or other body sites.
  • The bell of a stethoscope serves as an impedance matcher between the body and the air in the tube, requiring resonance of the sound frequency with the bell membrane.
  • The natural frequency of the bell depends on the diameter and tension of the diaphragm.

Sonic Spectrum

  • Sonic spectrum can be classified into three frequency ranges: infrasound, audible sound, and ultrasound.
  • The human ear can hear sounds in the range of roughly 20 Hz to 20 KHz.

Infrasound

  • Infrasound refers to sound frequencies below 20 Hz.
  • It is produced by natural phenomena like earthquake waves and atmospheric pressure changes.
  • Infrasound can travel long distances without losing much power and can travel through most media, making its effects difficult to minimize.
  • Intense infrasonic noise can produce respiratory impairment, aural pain, fear, visual hallucinations, and chills.
  • Infrasound can be used in the study of heart mechanical function, revealed by the seismocardiogram.

Ultrasound

  • Ultrasound is the frequency range above 20 KHz.
  • Ultrasound is used clinically in various specialties, providing more information than X-rays and being less hazardous for the fetus.

Intensity of a Sound Wave

  • The intensity I of a sound wave is the energy carried by the wave per unit area and per unit time (in units W/m²).
  • Intensity can be expressed by the maximum change in pressure.

Sound Intensity Level (Ratio)

  • The absolute value of sound intensity (I) cannot be measured; instead, it can be compared to a reference intensity (I₀).
  • The intensity ratio is the ratio of the sound intensity to the reference intensity.

Effect of Sound on Human Hearing

  • The human ear can distinguish two characteristics of sound: loudness and pitch.

General Properties of Sound

  • A sound wave is the pattern of disturbance caused by the energy traveling away from the source of the sound.
  • Sound is a mechanical disturbance that propagates through an elastic material medium with some definite velocity.
  • In air, sound can be defined as a local increase (compression) or decrease (rarefaction) of pressure relative to atmospheric pressure.
  • Sound travels fastest in solids, relatively slower in liquids, and slowest in gases.
  • The sound speed is given by: v = √(B/ρ), where B is the bulk modulus and ρ is the density of the medium.
  • The frequency of a sound wave is the number of rarefactions and compressions that occur per unit time, mathematically represented as: f = 1/T.
  • The wavelength of a sound wave is the distance between successive compressions and rarefactions, mathematically represented as: λ = v/f.

Sound Waves

  • Sound waves are patterns of disturbance caused by energy traveling away from the source of the sound.
  • Sound waves transfer energy without transferring matter.
  • Sound can be defined as a mechanical disturbance from a state of equilibrium that propagates through an elastic material medium with a definite velocity.

Classification of Sound Waves

  • Sound waves can be classified into three frequency ranges:
    • Infrasound: below 20 Hz
    • Audible sound: between 20 Hz and 20 KHz
    • Ultrasound: above 20 KHz

Human Hearing Range

  • The human ear can hear sounds in the range of roughly 20 Hz to 20 KHz.

Infrasound

  • Infrasound refers to sound frequencies below the normal hearing range (less than 20 Hz).
  • It is produced by natural phenomena like earthquake waves and atmospheric pressure changes.
  • Infrasound can travel long distances without losing much power due to its low absorption and large wavelength.
  • It can travel through most media, making its effects difficult to minimize.
  • Intense infrasonic noise can produce clear symptoms including:
    • Respiratory impairment
    • Aural pain
  • Other effects of infrasound may include:
    • Fear
    • Visual hallucinations
    • Chills
  • Infrasound can also be used in the study of heart mechanical function, revealed by the seismocardiogram.

Ultrasound

  • Ultrasound refers to sound frequencies above 20 KHz.
  • Ultrasound is used clinically in a number of specialties.
  • It often gives more information than an X-ray and is less hazardous for the fetus.

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