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overtones : all resonant frequencies higher than the fundamental
https://openstax.org/books/college-physics-2e/pages/17-glossary
phon : the numerical unit of loudness
https://openstax.org/books/college-physics-2e/pages/17-glossary
pitch : the perception of the frequency of a sound
https://openstax.org/books/college-physics-2e/pages/17-glossary
sonic boom : a constructive interference of sound created by an object moving faster than sound
https://openstax.org/books/college-physics-2e/pages/17-glossary
sound : a disturbance of matter that is transmitted from its source outward
https://openstax.org/books/college-physics-2e/pages/17-glossary
sound intensity level : a unitless quantity telling you the level of the sound relative to a fixed standard
https://openstax.org/books/college-physics-2e/pages/17-glossary
sound pressure level : the ratio of the pressure amplitude to a reference pressure
https://openstax.org/books/college-physics-2e/pages/17-glossary
timbre : number and relative intensity of multiple sound frequencies
https://openstax.org/books/college-physics-2e/pages/17-glossary
tone : number and relative intensity of multiple sound frequencies
https://openstax.org/books/college-physics-2e/pages/17-glossary
ultrasound : sounds above 20,000 Hz
https://openstax.org/books/college-physics-2e/pages/17-glossary
Sound is a disturbance of matter that is transmitted from its source outward.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Sound is one type of wave.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Hearing is the perception of sound.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The relationship of the speed of soundvwvw, its frequencyff, and its wavelengthλλis given by
https://openstax.org/books/college-physics-2e/pages/17-section-summary
which is the same relationship given for all waves.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
In air, the speed of sound is related to air temperatureTTby
https://openstax.org/books/college-physics-2e/pages/17-section-summary
vwvwis the same for all frequencies and wavelengths.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Intensity is the same for a sound wave as was defined for all waves; it isI=PA,I=PA,wherePPis the power crossing areaAA. The SI unit forIIis watts per meter squared. The intensity of a sound wave is also related to the pressure amplitudeΔpΔpI=(Δp)22ρvw,I=(Δp)22ρvw,whereρρis the density of the medium in which th...
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Intensity is the same for a sound wave as was defined for all waves; it is
https://openstax.org/books/college-physics-2e/pages/17-section-summary
wherePPis the power crossing areaAA. The SI unit forIIis watts per meter squared. The intensity of a sound wave is also related to the pressure amplitudeΔpΔp
https://openstax.org/books/college-physics-2e/pages/17-section-summary
whereρρis the density of the medium in which the sound wave travels andvwvwis the speed of sound in the medium.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Sound intensity level in units of decibels (dB) isβdB=10log10II0,βdB=10log10II0,whereI0=10–12W/m2I0=10–12W/m2is the threshold intensity of hearing.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Sound intensity level in units of decibels (dB) is
https://openstax.org/books/college-physics-2e/pages/17-section-summary
whereI0=10–12W/m2I0=10–12W/m2is the threshold intensity of hearing.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The Doppler effect is an alteration in the observed frequency of a sound due to motion of either the source or the observer.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The actual change in frequency is called the Doppler shift.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
A sonic boom is constructive interference of sound created by an object moving faster than sound.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
A sonic boom is a type of bow wake created when any wave source moves faster than the wave propagation speed.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
For a stationary observer and a moving source, the observed frequencyfobsfobsis:fobs=fsvwvw±vs,fobs=fsvwvw±vs,wherefsfsis the frequency of the source,vsvsis the speed of the source, andvwvwis the speed of sound. The minus sign is used for motion toward the observer and the plus sign for motion away.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
For a stationary source and moving observer, the observed frequency is:fobs=fsvw±vobsvw,fobs=fsvw±vobsvw,wherevobsvobsis the speed of the observer.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Sound interference and resonance have the same properties as defined for all waves.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
In air columns, the lowest-frequency resonance is called the fundamental, whereas all higher resonant frequencies are called overtones. Collectively, they are called harmonics.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The resonant frequencies of a tube closed at one end are:fn=nvw4L,n=1, 3, 5...,fn=nvw4L,n=1, 3, 5...,f1f1is the fundamental andLLis the length of the tube.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The resonant frequencies of a tube open at both ends are:fn=nvw2L,n=1, 2, 3...fn=nvw2L,n=1, 2, 3...
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The range of audible frequencies is 20 to 20,000 Hz.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Those sounds above 20,000 Hz are ultrasound, whereas those below 20 Hz are infrasound.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The perception of frequency is pitch.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The perception of intensity is loudness.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
Loudness has units of phons.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The acoustic impedance is defined as:Z=ρv,Z=ρv,ρρis the density of a medium through which the sound travels andvvis the speed of sound through that medium.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The intensity reflection coefficientaa, a measure of the ratio of the intensity of the wave reflected off a boundary between two media relative to the intensity of the incident wave, is given bya=Z2−Z12Z1+Z22.a=Z2−Z12Z1+Z22.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
The intensity reflection coefficient is a unitless quantity.
https://openstax.org/books/college-physics-2e/pages/17-section-summary
conductor : a material that allows electrons to move separately from their atomic orbits
https://openstax.org/books/college-physics-2e/pages/18-glossary
conductor : an object with properties that allow charges to move about freely within it
https://openstax.org/books/college-physics-2e/pages/18-glossary
Coulomb force : another term for the electrostatic force
https://openstax.org/books/college-physics-2e/pages/18-glossary
Coulomb interaction : the interaction between two charged particles generated by the Coulomb forces they exert on one another
https://openstax.org/books/college-physics-2e/pages/18-glossary
Coulomb’s law : the mathematical equation calculating the electrostatic force vector between two charged particles
https://openstax.org/books/college-physics-2e/pages/18-glossary
dipole : a molecule’s lack of symmetrical charge distribution, causing one side to be more positive and another to be more negative
https://openstax.org/books/college-physics-2e/pages/18-glossary
electric charge : a physical property of an object that causes it to be attracted toward or repelled from another charged object; each charged object generates and is influenced by a force called an electromagnetic force
https://openstax.org/books/college-physics-2e/pages/18-glossary
electric field : a three-dimensional map of the electric force extended out into space from a point charge
https://openstax.org/books/college-physics-2e/pages/18-glossary
electric field lines : a series of lines drawn from a point charge representing the magnitude and direction of force exerted by that charge
https://openstax.org/books/college-physics-2e/pages/18-glossary
electromagnetic force : one of the four fundamental forces of nature; the electromagnetic force consists of static electricity, moving electricity and magnetism
https://openstax.org/books/college-physics-2e/pages/18-glossary
electron : a particle orbiting the nucleus of an atom and carrying the smallest unit of negative charge
https://openstax.org/books/college-physics-2e/pages/18-glossary
electrostatic equilibrium : an electrostatically balanced state in which all free electrical charges have stopped moving about
https://openstax.org/books/college-physics-2e/pages/18-glossary
electrostatic force : the amount and direction of attraction or repulsion between two charged bodies
https://openstax.org/books/college-physics-2e/pages/18-glossary
electrostatic precipitators : filters that apply charges to particles in the air, then attract those charges to a filter, removing them from the airstream
https://openstax.org/books/college-physics-2e/pages/18-glossary
electrostatic repulsion : the phenomenon of two objects with like charges repelling each other
https://openstax.org/books/college-physics-2e/pages/18-glossary
electrostatics : the study of electric forces that are static or slow-moving
https://openstax.org/books/college-physics-2e/pages/18-glossary
Faraday cage : a metal shield which prevents electric charge from penetrating its surface
https://openstax.org/books/college-physics-2e/pages/18-glossary
field : a map of the amount and direction of a force acting on other objects, extending out into space
https://openstax.org/books/college-physics-2e/pages/18-glossary
free charge : an electrical charge (either positive or negative) which can move about separately from its base molecule
https://openstax.org/books/college-physics-2e/pages/18-glossary
free electron : an electron that is free to move away from its atomic orbit
https://openstax.org/books/college-physics-2e/pages/18-glossary
grounded : connected to the ground with a conductor, so that charge flows freely to and from the Earth to the grounded object
https://openstax.org/books/college-physics-2e/pages/18-glossary
grounded : when a conductor is connected to the Earth, allowing charge to freely flow to and from Earth’s unlimited reservoir
https://openstax.org/books/college-physics-2e/pages/18-glossary
induction : the process by which an electrically charged object brought near a neutral object creates a charge in that object
https://openstax.org/books/college-physics-2e/pages/18-glossary
ink-jet printer : small ink droplets sprayed with an electric charge are controlled by electrostatic plates to create images on paper
https://openstax.org/books/college-physics-2e/pages/18-glossary
insulator : a material that holds electrons securely within their atomic orbits
https://openstax.org/books/college-physics-2e/pages/18-glossary
ionosphere : a layer of charged particles located around 100 km above the surface of Earth, which is responsible for a range of phenomena including the electric field surrounding Earth
https://openstax.org/books/college-physics-2e/pages/18-glossary
laser printer : uses a laser to create a photoconductive image on a drum, which attracts dry ink particles that are then rolled onto a sheet of paper to print a high-quality copy of the image
https://openstax.org/books/college-physics-2e/pages/18-glossary
law of conservation of charge : states that whenever a charge is created, an equal amount of charge with the opposite sign is created simultaneously
https://openstax.org/books/college-physics-2e/pages/18-glossary
photoconductor : a substance that is an insulator until it is exposed to light, when it becomes a conductor
https://openstax.org/books/college-physics-2e/pages/18-glossary
point charge : A charged particle, designatedQQ,generating an electric field
https://openstax.org/books/college-physics-2e/pages/18-glossary
polar molecule : a molecule with an asymmetrical distribution of positive and negative charge
https://openstax.org/books/college-physics-2e/pages/18-glossary
polarization : slight shifting of positive and negative charges to opposite sides of an atom or molecule
https://openstax.org/books/college-physics-2e/pages/18-glossary
polarized : a state in which the positive and negative charges within an object have collected in separate locations
https://openstax.org/books/college-physics-2e/pages/18-glossary
proton : a particle in the nucleus of an atom and carrying a positive charge equal in magnitude and opposite in sign to the amount of negative charge carried by an electron
https://openstax.org/books/college-physics-2e/pages/18-glossary
screening : the dilution or blocking of an electrostatic force on a charged object by the presence of other charges nearby
https://openstax.org/books/college-physics-2e/pages/18-glossary
static electricity : a buildup of electric charge on the surface of an object
https://openstax.org/books/college-physics-2e/pages/18-glossary
test charge : A particle (designatedqq) with either a positive or negative charge set down within an electric field generated by a point charge
https://openstax.org/books/college-physics-2e/pages/18-glossary
Van de Graaff generator : a machine that produces a large amount of excess charge, used for experiments with high voltage
https://openstax.org/books/college-physics-2e/pages/18-glossary
vector : a quantity with both magnitude and direction
https://openstax.org/books/college-physics-2e/pages/18-glossary
vector addition : mathematical combination of two or more vectors, including their magnitudes, directions, and positions
https://openstax.org/books/college-physics-2e/pages/18-glossary
xerography : a dry copying process based on electrostatics
https://openstax.org/books/college-physics-2e/pages/18-glossary
There are only two types of charge, which we call positive and negative.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Like charges repel, unlike charges attract, and the force between charges decreases with the square of the distance.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
The vast majority of positive charge in nature is carried by protons, while the vast majority of negative charge is carried by electrons.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
The electric charge of one electron is equal in magnitude and opposite in sign to the charge of one proton.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
An ion is an atom or molecule that has nonzero total charge due to having unequal numbers of electrons and protons.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
The SI unit for charge is the coulomb (C), with protons and electrons having charges of opposite sign but equal magnitude; the magnitude of this basic charge∣qe∣∣qe∣is∣qe∣=1.60×10−19C.∣qe∣=1.60×10−19C.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Whenever charge is created or destroyed, equal amounts of positive and negative are involved.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Most often, existing charges are separated from neutral objects to obtain some net charge.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Both positive and negative charges exist in neutral objects and can be separated by rubbing one object with another. For macroscopic objects, negatively charged means an excess of electrons and positively charged means a depletion of electrons.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
The law of conservation of charge ensures that whenever a charge is created, an equal charge of the opposite sign is created at the same time.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Polarization is the separation of positive and negative charges in a neutral object.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
A conductor is a substance that allows charge to flow freely through its atomic structure.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
An insulator holds charge within its atomic structure.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Objects with like charges repel each other, while those with unlike charges attract each other.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
A conducting object is said to be grounded if it is connected to the Earth through a conductor. Grounding allows transfer of charge to and from the earth’s large reservoir.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
Objects can be charged by contact with another charged object and obtain the same sign charge.
https://openstax.org/books/college-physics-2e/pages/18-section-summary
If an object is temporarily grounded, it can be charged by induction, and obtains the opposite sign charge.
https://openstax.org/books/college-physics-2e/pages/18-section-summary