Final Exam Review Flashcards
amplitude
The distance from the midpoint to the maximum (crest) of a wave, or equivalently from the midpoint to the minimum (trough).
beat
Periodic variation in the loudness of sound. Caused when two tones of slightly different frequencies are sounded together.
compression
A pulse of compressed air. Example: consider a long room with a door at one end and an open window with a curtain at the other end. When you open the door, the compressed air moves from the door to the curtain until the curtain flaps out the window. This is an example of compression.
constructive interference
Addition of two or more waves when wave crests overlap to produce a resulting wave of increased amplitude.
crest
One of the places in a wave where the wave is highest or the disturbance is greatest.
destructive interference
Combination of waves where crests of one wave overlap troughs of another, resulting in a wave of decreased amplitude.
Doppler Effect
The apparent change in the frequency of a wave due to the motions of the source or of the observer.
frequency (f)
The number of events (cycles, vibrations, oscillations, or any repeated event.) per time, measured in hertz (or events per time). Inverse of period.
Hertz (Hz)
The SI unit of frequency. One hertz (Hz) us one cycle per second.
interference pattern
A pattern formed by the overlapping of two or more waves that arrive in a region at the same time.
longitudinal wave
A wave in which the individual particles of a medium vibrate back and forth along (parallel to) the direction in which the wave travels–for example, sound.
natural frequency
A frequency at which an elastic object naturally tends to vibrate, so that minimum energy is required to produce a forced vibration or to continue vibration at that frequency.
pitch
How low or how high we perceive a sound to be. The higher the frequency, the higher the pitch. For example, a foghorn would have a low pitch, and a piccolo would have a high pitch.
rarefaction
A disturbance in air (or matter) in which the pressure is lowered. Example: consider a long room with a door at one end and an open window with a curtain covering it on the other. When the door is closed, it creates an area of low pressure which causes the curtain to blow inward.
resonance
To “resound” or sound again. Occurs when the frequency of forced vibrations on an object matches the object’s natural frequency, causing a dramatic increase in amplitude.
standing wave
a wave that appears to stand in one place, even though it is really two waves interfering as they pass through each other
transverse wave
A wave with vibration at right angles to the direction the wave is traveling. Light consists of transverse waves.
trough
One of the places in a wave where the wave is lowest.
wavelength
The distance between successive identical parts of the wave (crest to crest, trough to trough, etc.).
alternating current
electric current that rapidly reverses in direction
ammeter
a device that measures current
amperes (A)
SI unit of electric current
1 ampere = 1 coulomb per second
angle of incidence
the angle between an incident ray and the normal to the surface it encounters
angle of reflection
the angle between an reflected ray and the normal to the surface of reflection
angle of refraction
the angle between a refracted ray and the normal to the surface at which it is refracted
capacitance (C)
the ability of an object to store electric charge
capacitor
a device used to store charge in a circuit
centi- (c)
one-hundredth
10-2
charging by conduction
transferring electric charge between objects by simple touching
charging by friction
transferring electric charge between objects by rubbing
charging by induction
redistributing electric charges in and on objects by the electrical influence of a charged object close by but not in contact
circuit
any complete path along which electric charge can flow
concave mirror
a mirror that curves inward like a “cave”
conductor
(a) a material in which heat can be transferred
(b) a material through which electric charge can flow (usually a metal)
converging lens
a lens that is thicker in the middle than at the edges and refracts parallel rays of light passing through it to a focus
convex mirror
a mirror that curves outward
the virtual image formed is smaller and closer to the mirror than the object
coulomb (C)
SI unit of electric charge
Coulomb’s Law
relationship among electrical force, charges, and distance
critical angle
the smallest angle of incidence for which a light ray is totally reflected within a medium
current (I)
the flow of electric charge that transports energy from one place to another
measured in amperes (amps for short)
direct current
electric current in which the flow of charge is always in one direction
diverging lens
a lens that is thinner in the middle than at the edges, causing parallel rays of light passing through it to diverge as if from a point
echo
a reflection of sound
electric charge (C)
a fundamental electric property to which the mutual attractions or repulsions between electrons or protons is attributed
electric field
a force field that fills the space around every electric charge or group of charges
measured by force per charge (Newtons/Coulomb)
electric potential energy
the energy that a charge has due to its location in an electric field
electric power (P)
the rate of electric energy transfer or the rate of doing work
power = current × voltage
electromagnetic spectrum
the range of electromagnetic waves extending from radio waves to gamma rays (low to high frequency)
RMI V UXG
electromagnetic wave
an energy-carrying wave emitted by vibrating charges (often electrons)
composed of oscillating electric and magnetic fields that regenerate one another
electron
a negative particle in the shell of an atom
Farad (F)
SI unit of capacitance
focal length
the distance between the center of a lens and either focal point
the distance from a mirror to its focal point
focal point
the point at which rays of light parallel to the principal axis converge (for a converging lens or concave mirror)
the point at which such rays appear to come (for a diverging lens or convex mirror)
fundamental frequency
lowest partial tone of a musical sound; also called first harmonic
giga- (G)
one billion
109
grounding
allowing charges to move freely along a connection from a conductor to the ground; often done for safety
harmonics
multiples of the fundamental frequency
Examples:
first harmonic = fundamental frequency × 1
second harmonic = fundamental frequency × 2
third harmonic = fundamental frequency × 3
index of refraction (n)
the ratio of the speed of light in a vacuum to the speed of light in another material
n = speed of lightvacuum / speed of lightmaterial
insulator
(a) a material that is a poor conductor of heat and that delays the transfer of heat
(b) a material that is a poor conductor of electricity
kilo- (k)
one thousand
103
law of reflection
the angle of incidence for a wave that strikes a surface is equal to the angle of reflection
light wave
the visible part of the electromagnetic spectrum
mechanical wave
wave that transfers energy through a medium
medium
a substance that makes possible the transfer of energy from one location to another
mega- (M)
one million
106
micro- (μ)
one-millionth
10-6
milli- (m)
one-thousandth
10-3
nano- (n)
one-billionth
10-9
normal
at right angles to, or perpendicular to
in optics, normal defines the line perpendicular to a surface about which angles of light rays are measured
a normal force acts at right angles to the surface on which it acts
Ohm’s Law
the current in a circuit is directly proportional to the voltage impressed across the circuit and is inversely proportional to the resistance of the circuit
V = IR
Ohm (Ω)
SI unit of electrical resistance
opaque
term applied to materials that do not allow light to pass through them
the material absorbs light without re-emmission resulting in a heat increase
parallel circuit
an electric circuit with two or more devices connected in such a way that the same voltage acts across each one
any single device completes the circuit independently of the others
penumbra
a partial shadow that appears where light from part of the source is blocked and light from another part of the source is not blocked
period (T)
time required to complete a single cycle
pico- (p)
one-trillionth
10-12
polarization
the aligning of vibrations in a transverse wave, usually by filtering out waves of other directions
primary colors of light
additive primary colors: three colors of light–red, green, and blue–that can be combined to produce any color
primary pigments
subtractive primary colors: three colors of light-absorbing pigments–magenta, yellow, and cyan–that can be combined to reflect any color
principal axis
the line joining the centers of curvature of the surfaces of a lens
the line joining the center of curvature and the focus of a mirror
proton
a positively charged particle that is one of the two kinds of nucleons in the nucleus of an atom
real image
an image formed by light rays that converge at the location of the image
a real image, unlike a virtual image, can be displayed on a screen
reflection
the return of light rays from a surface
refraction
bending of an oblique ray of light
resistance (R)
opposition of an object to the flow of electric charge through it
measured in Ohms (Ω)
resistor
a device in an electric field that is designed to resist the flow of charge
series circuit
an electric circuit with devices connected in such a way that the electric current through each of them is the same
shadow
a shaded region that results when light falls on an object and thus cannot reach into the region on the far side of the object
short circuit
a disruption in an electric circuit caused by the flow of charge along a low-resistance path between two points that should not be directly connected, thus deflecting the current from its proper path; an effective “shortening of the circuit”
Snell’s Law
sound
longitudinal wave phenomenon that consists of successive compressions and rarefactions of the medium through which the wave travels
speed of light
in a vacuum: 3 × 108 m/s
timbre
sound quality
total internal reflection
the 100% reflection (with no transmission) of light that strikes the boundary between two media at an angle larger than the critical angle
transparent
term applied to materials that allow light to pass through them in straight lines
umbra
the darker part of a shadow where all the light is blocked
virtual image
an image formed by light rays that do not converge at the location of the image
mirrors, converging lenses used as magnifying lenses, and diverging lenses all produce virtual images
the image can be seen by an observer but cannot be projected onto a screen
a real image, unlike a virtual image, can be displayed on a screen
visible light
part of the electromagnetic spectrum that the human eye can see
voltage (V)
electrical “pressure” or a measure of electrical potential difference
voltmeter
a galvanometer calibrated to read potential differences
Volts (V)
SI unit of electric potential
watt (W)
SI unit of power
1 watt = 1 joule per second
wave
a regularly repeating disturbance in a medium or a field that transports energy from one place to the next with no net transport of matter
a “wiggle in space and time”
wave speed
speed at which a wave passes a certain point
battery
a container in which chemical energy is converted into electricity and used as a source of power
beat frequency
the number of beats per second, equal to the difference in the frequencies of two interacting tones or oscillations
boundary
where two different media meet
conventional current
current as if it is caused by the flow of positive charges
conventional current flows from the positive terminal to the negative terminal
eclipse
the hiding of any heavenly body by another
solar eclipse: a complete or partial hiding of the sun caused by the moon’s passing between the sun and the earth
lunar eclipse: a darkening of the moon caused by its entering the shadow of the earth
electric field lines
they point in the direction that a positive test charge would accelerate
such lines are directed away from positively charged source charges and toward negatively charged source charges
electroscope
an early scientific instrument that is used to detect the presence and magnitude of electric charge on a body
electrostatic force
attraction or repulsion of particles or objects because of their electric charge
flat mirror
virtual image
left-right reversal of image
image distance = object distance
same size image
image distance
distance from an image to a mirror or lens
image height
height of an image produced by a mirror or lens
negatively charged
carrying a net negative charge
neutral
having no net charge
object distance
distance at which an object is placed from a mirror or lens
object height
actual height of an object
positively charged
carrying a net positive charge
radius of curvature
distance from the vertex (on the optical axis) to the center of curvature
schematic diagram
a means of describing an electric circuit is by use of conventional circuit symbols
triboelectric series
a list of materials, showing which have a greater tendency to become positive (+) and which have a greater tendency to become negative (−)
