Physics sound Flashcards by Amir Mostafavi

Sound wave is a ___ wave because the direction of the particles of the conducting medium oscillate is parallel to the direction the wave travels

Longitudinal wave

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Humans can perceive sound in the wave frequency range of __ and __

20 Hz to 20 kHz

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What are the two things that a sounds speed are dependent on?

The medium’s resistance to compression (quantified as the Bulk modulus) and its density

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Sound travels slowest throguh __ and fastest through__

Sound travels slowest through gases, then liquids and fastest through solids

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A siren produces sound waves in the air. If the frequency of the waves is gradually decreasing, what is most likely occuring to the waves?

The wavelengths are increasing, because the wave speed is set by the medium, the wave speed is constant
Since V= wavelength x frequency,
-Wavelength and frequency are inversely proportional, if f decreases the wavelength must increase

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__of a sound wave is the energy it tansmits per second (the power) per unit area

Intensity

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What are the units of intensity?

W/m^2

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The threshold of hearing, the lowest intensity the human ear can perceive as sound is equal to ___

1o^-12 W/m^2 intesntiy

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___ arises whenever a source of wave is moving relative to the detector, the result is that the perceived or detected frequency will be different from the frequency of the sound that was emitted from the source

Doppler effect

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If the detector moves toward the source of sound, or if the source of sound moves toward the detector, the detected frequency will be ___

higher than the emitted frequency

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If a detector moves toward (or away from) a stationary source, the relative speed of sound __

changes

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Sound travels faster through ___air because density is lower than colder air

Hotter

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The maximum displacement of a molecule in the medium disturbed in a sound wave is termed its __

amplitude

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__ is the amount of time it takes for one air molecule to complete 1 cycle as sound moves through it measured in seconds

Period

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Electromagnetic waves are ___

Transverse waves

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What is the order of colors from lowest frequency (longest wavelength) to highest frequency (shortest wavelength)

ROYGBV

Red, Orange, Yellow, Green, Blue, Violet

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As frequency increases, wavelength____

High frequency corresponds to shorter wavelength

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A low frequency will have a ___ wavelength

Long wavelength

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Wave-particle duality describes electromagnetic radiation as ___

EM radiation travels like a wave, but interacts with matter like a particle

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For an EM, energy is proportional to the square of ___

amplitude

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For particles (photons), energy is proportional to ___

frequency

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If EM radiation has a higher frequency then it has higher __

energy in photon (energy is proportional to frequency)

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The angle of reflection is equal to the angle of incidence

Law of reflection

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___is the angle that the transmitted (refracted) ray makes with the line that’s perpendicular to the plane of interface between two media

Angle of refraction

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When light travels through a material medium such as water or glass, its transmission speed is __

less than c (the speed it travels in a vacuum (equal for all types of light)

The greater the index of refraction for a medium___

the slower light travels through that medium

By Snell's law, if the transmitting medium has a higher index of refraction (n2) than the incident medium (n1) then___

the ray will bend toward the normal

By Snells law, if the transmitting medium (n2) has a lower index of refraction than the incident medium (n1) then__

The ray will bend AWAY from the normal

If the transmitting medium (n2) has a higher index of refraction than the incident medium (n1) then angle2 will be __

less than angle 1 (angle of incidence), the ray is bednign toward the normal

When light ray traveling in a medium of higher refractive index approaches a medium of lower refractive index (from water to air) it may or may not escape into the second medium, if the rays angle of incidence exceeds a certain critical angle, the light will undergo__

total internal reflection, all of the incident ray's energy will be reflectd back into the original medium, no refracted ray

If the angle of incidence is greater than the critical angle, then ___

total internal reflection will occur

IF when using snells law of reflection I find an angle of sin(0) > 1 (which is impossible, what does that mean?

It means there is NO ANGLE OF REFRACTION, there is TOTAL INTERNAL REFLECTION

The variation in amplitude of the resultant wave created by the interference of two waves with different frequencies. If f1 and f2 are the frequencies of the two waves, then the ___ frequency is given by f_ = | f1 - f2|

Beats

A ___ is a region where the local density and pressure is momentarily increased from standard due to the passage of sound wave

Compression

A __ is a mirror whose reflecting surface is curved toward the object so that its center is furthest from the object, it has a POSITIVE focal length

Concave mirror

A __ is a diverging lens, it has a NEGATIVE focal length

Concave lens

A lens that is thicker in the middle than in its edges. A __ causes incident parallel rays of light to converge to the focal point after passing through the lens

Converging lens

A __ is a mirror whose reflecting surface is curved away from the object; it has a NEGATIVE focal length

Convex mirror

A __ is a converging lens; it has a POSITIVE focal length

Convex lens

The redistribution of a wave's energy as it encounters and moves beyond an obstruction (or hole)

Diffraction

A lens that is thinner in the middle than at its edges. A __ causes an incident parallel rays of light to diverge away from the focal point after passing through the lens

Diverging lens

What is the order of increasing frequency of the electromagnetic spectrum?

Radio, microwaves, infrared light (IR), visible light, UV, X-ray, Gamma rays

The distance from a mirror or lens to its focal point along the axis of curvature.

Focal length

Concave mirrors and converging lenses have ___focal lengths

POSITIVE focal lengths

Convex mirrors and diverging lenses have ____focal lengths

NEGATIVE focal lengths

For a concave mirror or a converging lens, the focal point is ___

the point TO which rays of light that are initially paralll to the optical axis are focused after contact with the mirror or lens

For a convex mirror or a diverging lens, the focal point is ___

the point FROM which rays of light that are initially parallel to the optical axis are diverged after contact with the mirror or lens

The number of oscillations (cycles) per second

Frequency

Intensity is related directly to the ___

wave's amplitude and diminishes with the square of the distance from the source

A wave in which the oscillations of the medium are parallel to the direction of propagation of the wave

longitudinal waves (sound waves are longitudinal)

A thin piece of glass or plastic that forms an image by REFRACTING light

Lens

A surface that forms an image by REFLECTING light

Mirror

A negative value for the magnification means __

the image is INVERTED relative to the object

A transverse wave is __ if the direction of its oscillations is __

constant (confined to vary in a particular way)

In optics, __ is a measure of the focusing strength of al ens

Lens power P = 1/f

Energy emitted or absorbed due to propagation of waves (electromagnetic waves, unless a different kind of wave is specially mentioned)

Radiation

A region where the local density and pressure is momentarily decrease from standard due to the passage of a sound wave

Rarefaction

An image formed by a mirror or lens where the light rays actually DO intersect, it can be projected onto a screen

Real image

The change in direction of a wave when it passes from one medium to another

Refraction

When an incident beam of light strikes the surface of a medium with a lower index of refraction, the beam will experience ___ if the angle of incidence is GREATER than the critical angle. in this case none of the beam's energy is transmitted to the other medium; it is only reflected.

Total internal reflection

An image formed by a mirror or lens where light rays DON't actually intersect. A __ can't be displayed on a screen

Virtual image

Convex mirrors and divering (concave) lenses form ONLY___

virtual images

If the focal length f, and image distance i are positive, __

they are on the same side as the human observer in relation to the mirror or lens.

A positive value for i, image length, tells us __

the image is in front of the mirror and it is real

If we get a negative value for i, image length, tells us__

the image is virtual and behind the mirror

If m, magnification factor is positive __

The image is upright

If m, magnification factor is negative, __

the image is INVERTED

If i is POSITIVE then__

m is negative

If i is negative, then __

m is positive

Real images are __ and virtual images are __

real images are inverted and virtual images are upright

Concave mirrors can create ___ images

real and virtual images

Convex mirrors can only create ___

virtual images

___ are thicker in the middle than they are at the ends, and they refract light rays that are parallel to the axis toward the focal point on the other side of the lens

Converging lens

___ are thinner in the middle than they are at the ends, and they refract light rays that are parallel to the axis AWAY from the imaginary focal point that's in front of the lens

Diverging lens

When using lens equation, write the focal length of a CONVERGING lens as a ___

POSITIVE number

When writing the focal length of a DIVERGING lens write it as a __

NEGATIVE number

For a concave mirror, f is ___ and for a convex mirror f is ___

For a concave mirror f is positive | For a convex mirror, f is negative

For a concave lens f is __

negative

For a convex lens f is __

positive

For a lens, real images are formed on the ___

opposite side of the lens from the object

For lenses, virtual images are formed on __

same side of the lens as the object

A lens with a short focal length ____than a lens with a longer focal length

refracts light more than a lens with a longer focal length

A lens with a shorter focal length has __ than a lens with a longer focal length

GREATER POWER

Since the focal length of a converging lens is positive, the power of a converging lens is __

positive

Since the focal length of a diverging lens is negative, the power of a diverging lens is __

negative

Individuals with __ cannot focus clearly on distant objects

Myopia or nearsightedness

__ individuals are unable to focus clearly on objects that are near the eye

Hyperopia or farsightedness

___ is the term in which an eye's ability to accommodate is compromised by the loss of elasticity in the lens of the eye

Accomodation

__ refers to the ability to focus on nearby objects through the action of ciliary muscles, which essentially squeeze the lens of the eye

Accomodation

What type of lens is required to correct myopia and why?

Myopia is corrected with a diverging lens because a lens that "delays" the focus is required, a lens that diverges the parallel rays before they enter the lens of the eye so that they will focus beyond the focal point of the unaided eye and on the retina

What type of lens is required to correct Hyperopia and presbyopia and why?

A convering lens because the light rays are naturally focused beyond the retina in this condiiton. A lens that "accelerates" the focusing is required. A converging lens will converge the rays before they enter the lens of the eye so that they will focus in front of the focal point on the retina

If the angle of incidence is LESS than the critical angle __

light refracts AWAY from the normal

If the angle of incidence is EQUAL to the critical angle __

light refracts at 90 degrees to the normal

If the angle of incidence is GREATER than the critical angle

TOTAL INTERNAL REFLECTION OCCURS

A real image occurs whenever __

light rays converge at a point

A virtual image occurs because__

light rays APPEAR to converge at a point, but they don;t

Anytime you place an object between focal point and convex/converging lens you're going to have a __

virtual, upright, and enlarged image

For a concave mirror, the focal length is __

positive

For a convex mirror, the focal length is __

negative

For mirrors when di is positive_

Real image

For mirrors when di is negative___

Virtual image