physics unit 8
Refraction causes a definite interference pattern between waves as they are bent.
False, diffraction causes a definite interference pattern between waves as they are bent.
What effect does destructive interference have on the amplitude of a wave?
It tends to cancel the amplitude.
The interference between two sound waves of nearly identical frequency, amplitude and direction is called beats.
The statement is true and correct as written.
Multiple echoes, all mixed together, are called reverberation.
The statement is true.
What happens if crests correspond to crests, or troughs correspond to troughs?
You have constructive interference.
What happens if crests correspond to troughs?
You have destructive interference.
The light not reflected by the material is _________.
absorbed
At maximum ___________, the potential energy of a pendulum is maximum.
amplitude
The distance between the center line and the point farthest from the center line in a sine wave is called the _____.
amplitude
The distance between the center line and the point farthest from the center line in a wave is called the _____.
amplitude
Different wavelengths are refracted at different ____________.
angles
Different wavelengths of light are refracted at different ____________.
angles
What does the area marked indicate?
beats
Your eyes and your ___ work together to interpret certain wavelengths of light as particular colors.
brain
Unlike other types of electromagnetic waves, visible light can also be measured in terms of ______.
brightness
The formulas relating frequency, wavelength, and speed of an electromagnetic wave are _____ and _____.
c=fλ v=fλ
Sunlight is ___________ light, consisting of many colors blended together.
composite
The light produced by the sun is a _____ white light, made up of other colors of light.
composite
The type of mirror used in astronomical telescopes is a _______ or _______ mirror.
concave parabolic
The type of mirror used as a side view mirror in a car is a ______ mirror.
convex
According to Maxwell's law, a varying magnetic field induces a(n) _____.
electric charge
An electromagnetic wave starts with a vibrating _____.
electric charge
Light waves are formed just like any other type of __________ wave.
electromagnetic
Radio waves are an example of ___________ waves.
electromagnetic
All electromagnetic waves can be measured in terms of ___________.
energy
The angle of incidence and the angle of reflection are _____.
equal
The formula for the perceived frequency of a sound when a source is moving in relation to the hearer is ____________.
f = ( c/ c+-v) f0
The natural vibration of an object to a range of frequencies of sound is called beats.
false
The formula for the number of beats per second in the interference of two sound waves is ____________.
fbeat = f1-f2
The distance from the surface of a concave mirror to where a focused image is formed is called the ________ length.
focal
The distance from the surface of the concave mirror where a focused image is formed is called the ________ length.
focal
The pitch of a sound wave is determined by its _____________.
frequency
Ultrasonic waves have a very _____ frequency and very _____ wavelength.
high short
As the frequency of waves in the electromagnetic spectrum increases, the energy of a proton _______.
increases
The ratio of speed of light in a vacuum and the speed of light in a medium is called the _____.
index of refraction
Because they can penetrate smoke and clouds, the detection of __________ waves is useful in many professions.
infrared
Sounds below 20 Hz are called _____.
infrasonic
Colors are the result of the behaviors of light. Select the 4 examples mentioned in the lesson.
interference reflection diffraction refraction
What law governs the relationship between the distance form the source and the magnitude of an electromagnetic wave?
inverse-square law
A regular repeated motion caused by the exchange of energy from potential to kinetic energy and back again is called _____.
simple harmonic motion
The formula for Snell's law is _____.
sin 01/ sin 02 = v1/v2= n1/n2
An example of a mechanical wave is a _______ wave.
sound
Which is NOT an example of an electromagnetic wave?
sound
The _______ of sound depends on the medium.
speed
The index of refraction is found by dividing the speed of light in a vacuum by _____.
speed of light in the medium
Sound waves radiate in ____________ waves.
spherical
What is the effect on amplitude called in constructive interference?
the effect on the amplitude is called reinforcement
The symbol for wavelength is _____.
λ
The formula for calculating the spring constant _____.
k=F/x
(Double points) What is the wavelength of a gamma ray whose frequency is 3×1022 Hz? Use 3.00×108 m/s for c. For comparison, the diameter of a Uranium nucleus is approximately 1.5×10-14 m.
1.00 * 10 ^-14 m
(Triple points) What is the wavelength of a microwave whose frequency is 2.75×1010 Hz ? Use c=3.00×108 m/s.
1.09 * 10 ^-2 m
(Double points) An AM radio wave with a wavelength of 250 m travels at 3.00×108 m/s. What would be its frequency?
1.2 * 10^6 Hz
(Double points) What is the index of refraction of a material if the speed of light in that materials is 1.974x108 m/s ? Use 3.00x108 m/s for the speed of light in a vacuum.
1.520
(Double points) What is the index of refraction for a material if the speed of light in that material is 1.862x108 m/s?
1.611
(Double points) What is the speed of light in a medium if the index of refraction is 1.57?
1.91 * 10^8 m/s
What is the formula for the position at which a focused real image is formed by reflection in a concave mirror?
1/d i + 1/d o = 1/f
What is the range of frequencies of the electromagnetic spectrum?
10 Hz to upwards of 1025 Hz
No material ever reflects _______ of the light it receives.
100%
(Double points) If the height of the object is 2.5 cm in problem 8, how tall would the image be? Hint: The image height = object height X magnification. Magnification = Image distance / object distance (M=dido)
12.25 cm
(Triple points) A telescope has a focal length of 2000 mm. At what distance from the mirror will the image of an object 2000 m from the telescope appear?
2.002 m
A piano tuner is tuning a string which should have a frequency of 264 Hz. He knows the pitch is too low and he hears 3 beats per second. What is the frequency of the piano string?
261
(Double points) Radio waves travel at the speed of light. What is the wavelength of a radio signal with a frequency of 9.87×107
3.05 m
(Double points) An FM radio wave with a frequency of 94.1 mHz, which is 9.41 • 107 Hz travels at 3.00 • 108 m/s. What would be its wavelength?
3.19 m
(Triple points) A telescope has a focal length of 2000 mm. At what distance from the mirror will the image of an object 5 m from the telescope appear?
3.33 m
(Double points) What is the wavelength of a violet light whose frequency is 7.28×1014 Hz? Use 3.00×108 m/s for c .
4.12 * 10 ^-7 m
The frequencies of visible light vary from _____.
4.3 X 1014 Hz to 7.5 X 1014 Hz
(Double points) What is the frequency of a red light whose wavelength is 6.87×10-7 m?
4.37 *10 ^15 Hz
The wavelengths of visible light vary from _____.
400 nm to 700 nm
A piano tuner is tuning a string which should have a frequency of 440 Hz. He knows the pitch is too high and he hears 5 beats per second. What is the frequency of the piano string?
445
(Triple points) An ambulance is moving away from you at 25 m/s. Its siren has a frequency of 750 Hz. What frequency will you perceive the siren's sound to be? Use 346 m/s for the speed of sound.
699
(Triple points) An ambulance siren has a frequency of 800Hz and is moving away from you at 30 m/s. What frequency will you perceive? Use 346 for the speed of sound.
876 Hz
Andi is sitting on the edge of a swimming pool creating a series of circular waves by dipping her feet in the water. The waves undergo interference and create a patterns represented in the diagram below. The thick lines in the diagram represent wave crests and the thin lines represent wave troughs. Several positions in the water are labeled with a letter. Indicate the labels that demonstrate constructive interference.
A B
The _________ effect is the increasing or decreasing of the frequency at the hearer as the source approaches or recedes.
Doppler
The _________ effect is the phenomenon of a changing distance between source and hearer.
Doppler
Andi is sitting on the edge of a swimming pool creating a series of circular waves by dipping her feet in the water. The waves undergo interference and create a patterns represented in the diagram below. The thick lines in the diagram represent wave crests and the thin lines represent wave troughs. Several positions in the water are labeled with a letter. Indicate the labels that demonstrate destructive interference.
F D C E
An electromagnetic wave with wavelength 350 m is visible light.
False
Different kinds of electromagnetic waves travel at different speeds in a vacuum.
False
Electric and magnetic fields create mechanical waves.
False
Electromagnetic waves travel at the same speed in a different medium such as air as they do in a vacuum.
False
Loudness is measured in deciwatts, the intensity of one sound relative to the intensity of another.
False, loudness is measured in decibels, the intensity of one sound relative to the intensity of another.
The area between two compressions is called a reflection.
False, the area between two compressions is called a rarefaction.
The distance between the center line and the point farthest away from the center line is called the period of the wave.
False, the distance between the center line and the point farthest away from the center line is called the amplitude of the wave.
The natural vibration of an object to a range of frequencies of sound is called consonance.
False, the natural vibration of an object to a range of frequencies of sound is called resonance.
The reason there is no "shadow" effect cast by objects when it comes to sound is echo.
False, the reason there is no "shadow" effect cast by objects when it comes to sound is diffraction.
___________ excite water molecules in the food and causes the food to cook from the inside.
Microwaves
___________ can have an effect in the speed of sound.
Temperature
The formula for period of oscillation of a pendulum is _____.
Tp=2pi √L/g
The electrical and magnetic fields of an electromagnetic wave are perpendicular to each other and to the direction of travel.
True
Diffraction of multiple light waves will cause a complex set of bands to form, some bright because of constructive interference and some dark because of destructive interference.
True, correct as written.
If a light wave enters a medium having a higher index of refraction than the medium it is leaving, the light wave will bend toward the normal line.
True, correct as written.
The bending of waves around an edge is called diffraction.
True, correct as written.
__________ are used in medical professions to produce images of the structures in the body.
X-rays
The reflected image in a mirror will always be slightly ____ than the original object.
darker
Loudness is measured in __________.
decibels
As the frequency increases, the wavelength _____.
decreases
As the frequency of waves in the electromagnetic spectrum increases, the wavelength _______.
decreases
As wavelength increases, frequency decreases _____ and as wavelength decreases, frequency ____
decreases increases
As wavelength increases, frequency _____ and as wavelength decreases, frequency _____.
decreases increases
As wavelength increases, frequency______ and as wavelength decreases, frequency ______.
decreases increases
The thick lines in the diagram represent wave crests and the thin lines represent wave troughs. Categorize the indicated point as a position of destructive or constructive interference.
destructive
What type of interference is shown in the area marked?
destructive
What are the types of interference?
destructive constructive
(Triple points) A convex lens has a focal length of 10 cm. The object distance is 12 cm. How far from the lens would the image be in focus?
di= -58.82 cm in opposite direction of object
The speed of sound is _____ in different media.
different
The effect amounts to a change in ________ and ________ of the waves.
direction speed
To calculate the spring constant, divide the force by the _____.
displacement
At equilibrium in a pendulum, the potential energy is zero and the velocity is ________.
distance
The magnitude of an electromagnetic wave and the _____ vary in an inverse-square relationship.
distance
During a pendulum's motion, the total mechanical energy _____.
does not change
___________ rays can both cause cancer and be used in its treatment
gamma
___________ rays can both cause cancer and be used in its treatment.
gamma
The angle formed by the incoming ray and a perpendicular line is called angle of __________.
incidence
Sound waves radiate in spherical ___________ waves.
longitudinal
According to Faraday's law, a varying electric field creates a(n) _____.
magnetic field
5) Select two formulas for index of refraction.
n= c/v c=nv
A line that is perpendicular to a surface is called a(n) _____ line.
normal
The angles light travels as it passes from one medium to another are measured just as they are in reflection, using a _____ line.
normal
The electrical and magnetic fields of an electromagnetic wave are _____________ to each other and to the direction of travel.
perpendicular
The magnitude of light is subject to an inverse-square law between its _____ at the source and the ____ from the source
power distance
The magnitude of light is subject to an inverse-square law between its____ at the source and the _____.
power distance
A ___________ may be used to split light into its component colors.
prism
Electromagnetic waves with the lowest frequencies are ______ waves.
radio
In a concave mirror, a second type of image is formed, inverted and smaller than the original object. This image is called a(n) ________ image.
real
Light with a frequency of 4.55×1014 Hz will appear to be what color?
red
The lowest frequencies of light that we can see are perceived as _____.
red
Leaves appear green because the leaves _____ green light.
reflect
It is the ________ wavelengths of light that give an object its color.
reflected
When we see an object, we see light that is __________ from it.
reflected
When we see an object, we see light that is __________ from it.
reflected
The angle formed by the reflected ray and the normal line is called the angle of ____________.
reflection
A rose appears red because the rose ___ red light.
reflects
The effect of light entering a new medium is called _____.
refraction
The natural vibration of an object to a range of frequencies of sound is called __________.
resonance
The reflected image in a flat mirror is always ______.
reversed
The reflected image in a flat mirror is always _____ and its called _____ image.
reversed virtual
The reflected image in a flat mirror is always _____ and its called _____ image
reversed virtual
The sky appears blue because light from the sun is refracted and ______ in the atmosphere.
scattered
Blue light is _____ more than other colors so the sky appears ____.
scattered blue
If a light wave enters a medium having a higher index of refraction than the medium it is leaving, the light wave will bend ________ the normal line.
toward
______ materials allow waves in the visible range of light to pass through while _____ materials stop light waves.
transparent opaque
Waves that are perpendicular to the line of travel are called ___________ waves.
transverse
Loudness is measured in decibels.
true
Most animals have organs that are sensitive to light.
true
When the eye sees light, it sends signals to the brain through nerves where they are interpreted.
true
Sounds above 20,000 Hz are called:
ultrasonic
Exposure to _______ light causes the body to produce vitamin D.
ultraviolet
The formula for speed of a wave is _____.
v=fλ
Light with the shortest wavelengths that we can see appears as _____.
violet
The reflected image in a flat mirror is called __________ image.
virtual
The distance between two corresponding points in consecutive wave crests is called _____.
wavelength
2) Select three examples of electromagnetic waves.
x-rays lights microwaves
Light with a wavelength of 580 nm will most likely appear to be what color?
yellow
Two waves traveling along the same line will ______ with each other.
interfere
Wavelength and frequency are ________ related.
inversely
(Double points) The frequency of A above middle C on a piano keyboard is 440 Hz. What is the wavelength of the sound wave of this note? Assume the speed of sound to be 343 m/s.
.78 m
(Double points) The frequency of C one octave above middle C is exactly double the frequency of middle C which is 264 Hz. What is the wavelength of the sound wave of this note? Assume the speed of sound to be 343 m/s.
0.65 m
(Triple points) What is the period of oscillation of a spring system with a spring constant of 2.5 N/m if the mass attached is 10 kg?
12.56 s T=2πmk, so Tp=2(3.14)102.5=2(3.14)4=2(3.14)(2)=12.56 s
(Double points) In aluminum, the speed of sound is 5100 m/s. What is the wavelength of a sound wave of middle C at 264 Hz traveling through aluminum?
19.32 m
The speed of light in a vacuum is _____.
3.00 * 10 ^8 m/s
Radio waves travel at the speed of light. What is the wavelength of a radio signal with a frequency of 9.87×107 Hz ?
3.04 m
(Double points) Radio waves travel at the speed of light. Jayke listens to a radio station at 98.3 mHz., which is a frequency of 9.83×107 Hz . What is the wavelength of this radio signal in a vacuum?
3.05 m
(Double points) Calculate the period of oscillation of a pendulum with a small amplitude whose length is 2.5 meters.
3.14 s
Radio waves travel at the speed of light. Marsha listens to a radio station at 91.3 mHz., which is a frequency of 9.13×107 Hz. What is the wavelength of this radio signal in a vacuum?
3.29 m
(Triple points) Calculate the period of oscillation of a pendulum with a small amplitude whose length is 3 meters.
3.47 s
(Double points) In seawater , the speed of sound is 1530 m/s. What is the wavelength of a 440 Hz tone in seawater?
3.48 m
At equilibrium the pendulum has kinetic energy totaling 32 joules. Calculate the potential energy and the mechanical energy of the pendulum at equilibrium.
32 J 0 J
(Double points) C three octaves below middle C has a wavelength of 10.4 m. What is the frequency? Assume the speed of sound to be 343 m/s.
32.98 Hz
The speed of sound in air at sea level and 0 °C is _____.
343 m/s
(Triple points) An ambulance siren has a frequency of 800 Hz. You perceive the sound of the ambulance siren to have a frequency of 700 Hz. How fast is the ambulance moving away from you? Use 343 m/s for the speed of sound.
49 m/s
This graph shows the interaction of two waves. Several positions along the medium are labeled with a number. Check each labeled position along the medium as being a position where destructive interference occurs.
5 2 9 6 3
How many beats per second will piano tuner hear while turning middle C when the frequency of his tuning fork is 264 Hz and the frequency of the string he is tuning is 269 Hz?
5 beats per second
(Double points) A 5 kg mass is suspended from a spring. The spring is stretched 8 cm from equilibrium. What is the spring constant? Use g=9.8 m/s2 to calculate the force of the load.
612.5 N/m
(Double points) Placing a 500 kg load in the bed of a pick up truck displaces the truck 8 cm toward the ground. What is the spring constant of the truck? Use g=9.8 m/s2 to calculate the force of the load.
61250 N/m
This graph shows the interaction of two waves. Several positions along the medium are labeled with a number. Check each labeled position along the medium as being a position where constructive interference occurs.
7 4 1 8
12) Matching.
A= rarefaction B=compression
11) Matching.
A= wavelength B= amplitude C= crest D= trough
To find the speed of the wave in a medium, multiply the ______ of a wave by its ____ in the medium.
Frequency wavelength
What effect does constructive interference have on the amplitude of a wave?
It tends to reinforce the amplitude.
(Double points) At one point in a pendulum's oscillation, its potential energy is 25% of its mechanical energy. If PE = 20 J, what is KE, the kinetic energy , and ME, the mechanical energy of the pendulum?
KE = 60 J; ME = 80 J
Waves that require a medium such as air, water, or another material are called ______. An example of this type are ______ waves.
Mechanical Sound
The formula that shows the conservation of mechanical energy in simple harmonic motion is _____.
PE+KE=PE+KE
Sounds below 20 Hz are called:
infrasonic
The formula for period of oscillation of a spring is _____.
T= 2pi√m/k
The intensity of a sound wave is related to the surface area of a sphere at any distance from the source of the sound and is a measure of the power of the sound.
The statement is true.
The distance between two similar points in consecutive pulses is represented by the Greek letter λλ and is called wavelength.
True, sentence is correct as written.
The highest point of a transverse wave is called a crest and the lowest point is called a trough.
True, sentence is correct as written.
Waves that vibrate parallel to the line of travel are called longitudinal waves.
True, sentence is correct as written.
The maximum displacement of a pendulum is called the _____.
amplitude
What type of interference is shown in the area marked?
constructive
A position of ________ in a pendulum means that there is no actual force in effect.
equilibrium
The symbol for frequency is _____.
f
The results of the Doppler effect is a shift in _____ of the sound.
frequency
In a pendulum, the period of oscillation for small amplitude depends on the _____.
length
Sound waves are _____ waves.
longitudinal compression
In a spring, the period of oscillation depends on the spring constant and the _____.
mass
At equilibrium in a pendulum, the potential energy is zero and the velocity is ________.
maximum
At maximum amplitude, the potential energy of a pendulum is _____ while the acceleration and velocity are both zero.
maximum
Waves that require a medium such as air, water, or another material are called ____________.
mechanical
The speed of a wave will vary depending on the _______ through which it is traveling.
medium
Waves that do not require a medium for travel are called _____. An example of this type of wave is______ waves.
non mechanical Electromagnetic
The amount of time it takes for a pendulum to complete one cycle is called the _____.
period of oscillation
A collection of repeating pulse waves is called ___________.
periodic
A wave that is a one time occurrence, has an immediate cause, and lasts for just a moment is called a(n) ___________ wave.
pulse
An echo is caused by a ________ sound wave.
reflected
In a spring, the period of oscillation depends on the mass and the _____.
spring constant
The strength of a spring is called _____.
spring constant
If two waves have the same amplitude and the same frequency but the crests of one wave exactly correspond to the troughs of the other wave, what will the result of the inference be?
total cancellation
Because they are not matter, ______ can occupy the same place at the same time.
waves
