Physics sound Flashcards
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
Humans can perceive sound in the wave frequency range of __ and __
20 Hz to 20 kHz
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
Sound travels slowest throguh __ and fastest through__
Sound travels slowest through gases, then liquids and fastest through solids
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
__of a sound wave is the energy it tansmits per second (the power) per unit area
Intensity
What are the units of intensity?
W/m^2
The threshold of hearing, the lowest intensity the human ear can perceive as sound is equal to ___
1o^-12 W/m^2 intesntiy
___ 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
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
If a detector moves toward (or away from) a stationary source, the relative speed of sound __
changes
Sound travels faster through ___air because density is lower than colder air
Hotter
The maximum displacement of a molecule in the medium disturbed in a sound wave is termed its __
amplitude
__ is the amount of time it takes for one air molecule to complete 1 cycle as sound moves through it measured in seconds
Period
Electromagnetic waves are ___
Transverse waves
What is the order of colors from lowest frequency (longest wavelength) to highest frequency (shortest wavelength)
ROYGBV
Red, Orange, Yellow, Green, Blue, Violet
As frequency increases, wavelength____
High frequency corresponds to shorter wavelength
A low frequency will have a ___ wavelength
Long wavelength
Wave-particle duality describes electromagnetic radiation as ___
EM radiation travels like a wave, but interacts with matter like a particle
For an EM, energy is proportional to the square of ___
amplitude
For particles (photons), energy is proportional to ___
frequency
If EM radiation has a higher frequency then it has higher __
energy in photon (energy is proportional to frequency)
The angle of reflection is equal to the angle of incidence
Law of reflection
___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
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
