Chapter 14 Waves
Notes
12/2013
What is a Wave?
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A ___________________ is a periodic disturbance in a solid, liquid, or gas as energy is
transmitted through a medium.
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Waves carry energy through ___________________________________________.
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Most waves travel through a _______________________________.
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The matter through which a wave travels is called the _____________________________.
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Waves that require a medium are called _______________________________________________.
Light does not require a medium.
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Light waves consist of changing electric and magnetic fields in space.
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Light waves are called _________________________________________________.
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An _____________________________________________________ consists of oscillating electric and
magnetic fields, which radiate outward at the speed of light.
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Waves transfer ______________________.
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Energy may spread out as a wave travels.
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When sound waves travel in air, the waves spread out in ___________________. As they
travel outward, the spherical wave fronts get bigger, so the energy in the waves
spreads out over a larger area.
Vibrations and Waves
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Waves are related to __________________________________________.
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Most waves are caused by a _________________________________ object.
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Electromagnetic waves may be caused by vibrating charged particles.
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In a mechanical wave, the particles in the __________________________ also vibrate as the
wave passes through the medium.
Vibrations involve _______________________________________________ of energy.
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Whenever a spring is expanded or compressed, it is exerting a force that pushes the mass
back almost to the _________________________________________________________________.
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As a result, the mass will continue to bounce up and down.
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This type of vibration is called _____________________________________________________________.
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A wave can pass through a _______________________ of vibrating objects.
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If the first mass were not connected to the other masses, it would keep vibrating up and
down on its own. However, because it transfers its energy to the second mass, it ____________
down and then returns to its resting position.
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A vibration that fades out as energy is transferred from one object to another is
called ____________________________________________________________________________.
The motion of particles in a medium is like the motion of masses on springs.
Transverse and Longitudinal Waves
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Particles in a medium can vibrate either ______________________________________________________.
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Waves are often classified by the _________________________________________ that the particles in
the medium move as a wave passes by.
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Transverse waves have _______________________________________________ motion.
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A _________________________________________ wave is a wave in which the particles of the medium
move perpendicular to the direction the wave is traveling.
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_____________________________ waves are transverse waves.
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Longitudinal waves have __________________________________ motion.
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A ___________________________________________ wave is a wave in which the particles of the
medium vibrate parallel to the direction of wave motion.
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____________________________ waves are longitudinal waves.
In a __________________________ wave, particles move in ______________________.
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Surface waves occur at the _______________________________ between two different
mediums, such as between ______________________________________________.
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The particles move both perpendicularly and parallel to the direction that the wave
travels.
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Wave Properties
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An ideal transverse wave has the shape of a ______________________________________________.
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Waves that have the shape of a sine curve are called ____________________________________.
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____________________________ measures the amount of particle vibration.
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The __________________________ is the highest point of a transverse wave.
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The ____________________________ is the lowest point of a transverse wave.
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The ____________________________ is the maximum distance that the particles of a wave’s
medium vibrate from their rest position.
A longitudinal wave has compressions and rarefactions.
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The crowded areas are called ___________________________________________.
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The stretched-out areas are called ______________________________________.
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The ___________________________ of a longitudinal wave is the maximum deviation from
the normal density or pressure of the medium.
Wavelength measures the ______________________________ between two equivalent parts of a
wave.
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The ________________________________________ is the distance from any point on a wave to
an identical point on the next wave.
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Not all waves have a single wavelength that is easy to measure.
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Wavelength is represented by the Greek letter _____________________________________.
The period measures how ______________________ it takes for waves to pass by.
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The _______________________ is the time that it takes a complete cycle or wave oscillation
to occur.
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The period is represented by the symbol ______.
Frequency measures the _________________ of vibrations.
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The ______________________________ is the number of cycles or vibrations per unit of time.
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The symbol for frequency is _____.
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The frequency and period of a wave are related.
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The SI unit for measuring frequency is _____________________.
The frequency is the ______________________ of the period.
Light comes in a wide range of frequencies and wavelengths.
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Our eyes can detect light with frequencies ranging from about 4.3  1014 Hz to 7.5 
1014 Hz.
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Light in this range is called ______________________________________________.
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The full range of light at different frequencies and wavelengths is called the
___________________________________________________________________________.
Visible Light
The Electromagnetic Spectrum
Wave Speed
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Wave speed equals frequency times wavelength.
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The speed of a wave depends on the __________________________.
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In a given medium, though, the speed of waves is ____________________________; it does
not depend on the frequency of the wave.
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___________________________________________________ explains differences in wave speed.
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The arrangement of particles in a medium determines how well waves travel
through it.
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In ______________________, the molecules are far apart and move around
randomly. Waves don’t travel as fast in gases.
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In _______________________, such as water, the molecules are much closer
together. But they are also free to slide past one another.
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In a ______________________, molecules are not only closer together but also
tightly bound to each other. Waves travel very quickly through most solids.
Light has a ____________________________ speed.
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All electromagnetic waves in empty space travel at the same speed, the speed of
light, which is:
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Light travels ______________________ when it has to pass through a medium such as air
or water.
Doppler Effect
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Pitch is determined by the frequency of sound waves.
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The ________________________ of a sound, how high or low it is, is determined by the
frequency at which sound waves strike the eardrum in your ear.
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A higher-pitched sound is caused by sound waves of ____________________ frequency.
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Frequency changes when the source of waves is ___________________________.
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The ___________________________________________ is an observed change in the frequency of
a wave when the source or observer is moving.
Reflection, Diffraction, Refraction
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____________________________________ is the bouncing back of a ray of light, sound, or heat when
the ray hits a surface that it does not go through.
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Waves reflect at a free boundary.
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The reflected wave is exactly like the original wave except that the reflected wave is
traveling in the _________________________ direction to the direction of the original wave.
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At a fixed boundary, waves reflect and turn upside down.
Diffraction is the _____________________________ of waves around an edge.
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________________________________ is a change in the direction of a wave when the wave
finds an obstacle or an edge, such as an opening.
Waves can also bend by __________________________.
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__________________________________ is the bending of a wavefront as the wavefront passes
between two substances in which the speed of the wave differs.
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All waves are refracted when they pass from one medium to another at an angle.
Interference
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Waves in the same place ________________________________ to produce a single wave.
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__________________________________________ is the combination of two or more waves of the
same frequency that results in a single wave.
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The resulting wave can be found by ____________________________ the height of the
waves at each point.
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Crests are considered positive, and troughs are considered negative.
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This method of adding waves is sometimes known as the
______________________________________________________________________________________
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Constructive interference ______________________________ amplitude.
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_______________________________________________________________ is any interference in which
waves combine so that the resulting wave is bigger than the original waves.
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The amplitude of the resulting wave is the sum of the amplitudes of the two
individual waves.
Destructive interference _____________________________ amplitude.
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________________________________________________________ is any interference in which waves
combine so that the resulting wave is smaller than the largest of the original waves.
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When destructive interference occurs between two waves that have the same
amplitude, the waves may completely cancel each other out.
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Interference of light waves creates ______________________________ displays.
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Interference of sound waves produces __________________________.
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When two waves of slightly different frequencies interfere with each other, they
produce beats.
Standing Waves
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Interference can cause ________________________ waves.
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A _____________________________________________________ is a pattern of vibration that
simulates a wave that is standing still.
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Standing waves can form when a wave is _______________________________ at the
boundary of a medium.
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Although it appears as if the wave is standing still, in reality waves are traveling in
_________________________________________________________.
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Standing waves have ___________________ and _____________________________.
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Each loop of a standing wave is separated from the next loop by points that have
____________________________________________, called nodes.
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Midway between the nodes lie points of _________________________________________, called
antinodes.
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Nodes lie at the points where the crests of the original waves meet the
troughs of the reflected waves, causing complete destructive interference.
Antinodes form where the crests of the original waves line up with the crests
of the reflected waves, causing complete constructive interference.
Standing waves can have only certain __________________________________.
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In general, standing waves can exist whenever a multiple of
_________________________________________________ will fit exactly in the length of the string.
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It is possible for standing waves of more than one wavelength to exist on a string at
the same time.
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