Physics Chapter 19 Waves: Practice Test, ChTest, Homework and Terms
If the Frequency of a certain wave is 10 hertz, its period is
0.1 second
The frequency of a certain wave is 10 hertz and its period is
0.1 second
A weight suspended from a spring bobs up and down over a distance of 1 meter in two seconds. Its frequency is
0.5 Hz
A sound wave with frequency of 246Hz travels at a speed of 346.2. What is the Wavelength
1.4
If the frequency of a particular wave is 20 Hz, its period is
1/20 second
A 101-MHz radio wave has vibrations per second of
101,000,000
How many vibrations per second are represented in a radio wave of 101.7 MHz
101,700,000 vibrations
A water wave passes by a floating leaf that is made to oscillate up and down two complete cycles each second, which means that the wave's frequency is
2Hz
The amplitude of a wave is 1 meter. The crest-to-trough distance of the wave is
2m
Radio waves travel at the speed of light, 300, 000km/s. The wavelength of a radio wave received at 100megahertz is
3.0
Radio waves travel at the speed of light, 300,000 km/s. The wavelength of a radio wave received at 100 megahertz is
3.0m
What is the wave speed of a wave traveling an average distance of 6 meters in one second
6 m/s
A 60-vibration-per-second wave travels 30 meters in 1 second. Its frequency is
60 hertz and it travels at 30 m/s.
An object that completes 10 vibrations in 20 seconds has a frequency of
= .5 Hz
A bow wave on the surface of water is two-dimensional. What about a shock wave in air
A shock wave in air is three-dimensional
What is a wiggle in time called? What do you call a wiggle in space and time?
A vibration, a wave
Longitudinal Wave
A wave in which the medium vibrates parallel to the direction in which the wave travels. Sound waves are longitudinal waves
Transverse Wave
A wave in which the medium vibrates per pendicularly (at right angles) to the direction in which the wave travels. Light waves are waves on stringed instruments are transverse
What kinds of waves can show interference
All waves show interference.
Some of a wave's energy dissipates as heat. In time, this will reduce the wave's
Amplitude
What is meant by a blue shift and a red shift for light?
An approaching source has increased light frequency - a blue shift. A receding source has a decreasing frequency - a red shift
In what direction are the vibrations relative to the direction of wave travel in a transverse wave
At right angles to the direction of wave travel
The vibrations of a transverse wave move
At right angles to the direction of wave travel
A red shift for light indicates that the light source is moving
Away from you
Can the Doppler effect be observed with longitudinal waves or with transverse waves
Both
Distinguish between constructive interference and destructive interference
Constructive interference occurs when the crests of two waves add together. Destructive interference occurs when a crest of one wave is reduced by the trough of another.
Distinguish between constructive interference and destructive interference.
Constructive interference occurs when the crests of two waves add together. Destructive interference occurs when a crest of one wave is reduced by the trough of another.
A wave oscillates up and down two complete cycles each second. If the wave travels and Average Distance of 6 meters in one second, its wavelength is
Cycles(Hz)/meters = Wavelength 6m/2hz=3m
If you take a given pendulum to the Moon, where the acceleration of gravity is less than on Earth, the resonant frequency of the pendulum will
Decrease
A Doppler effect occurs when a source of sound moves
Either Towards you or Away from you
If waves are going by at the same speed, the wave with the greatest period of oscillation is the wave that has the greatest amplitude, length, and frequency
False
Amplitude
For a wave or vibration, the maximum displacement on either side of the equilibrium (mid point) position
Frequency
For vibrating body or medium, the number of vibrations per unit time. For a wave, the number of crests that pass a particular point per unit time
How are frequency and period related to each other
Frequency and period are inversely proportional
If you double the frequency of a vibrating object, its period
Halves
If at a concert, a wind blows directly from the orchestra toward you, the speed of the sound you hear will be
Increased
If you quickly run toward the orchestra at a concert, the frequency of the sound you hear will be
Increased
The Frequency of a simple pendulum depends on
It's Length and the Acceleration due to gravity
The frequency of a simple pendulum does NOT depend on
Its Mass
Does the medium in which a wave travels move with the wave
No
The number of nodes, including the end points, in a standing wave that is two wavelengths long is
Not 1-4
In the Doppler effect, does frequency change? Does wave speed change
Only frequency changes
In what direction are the vibrations relative to the direction of wave travel in a longitudinal wave
Parallel to the direction of wave travel
A pendulum clock at high altitudes runs
Slow
Hertz
The SI unit of Frequency. One hertz (hz) equals one vibrations per second
Wavelength
The distance between successive crests, troughs or identical parts of a wave
Which has the longer period, a short or a long pendulum
The long pendulum has the longer period.
The spectrum of a quasar shows an emission line with a wavelength five times longer than the wavelength it would have if it were stationary. What can we conclude
The quasar is moving away from us near the speed of light. (When an object is moving away from us near the speed of the light, the redshift is very large).
what is the source of all waves
The source is something that is vibrating
What is the source of all waves
The source is something that is vibrating.
Period
The time in which a vibration is completed. The period of a wave equals the period of the source and is equal to 1/ frequency
Sine Curve
The waveform traced by simple harmonic motion, which can be made visible on a moving conveyor belt by a pendulum swinging at right angles above the moving belt
The wavelength of a transverse wave is the distance between successive crests (or troughs). What is the wavelength of a longitudinal wave
The wavelength is the distance between successive maximum compressions (or rarefractions).
If a star is moving away from you at a constant speed, how do the wavelengths of the absorption lines change as the star gets farther and farther
The wavelengths remain the same. (Since the star's velocity isn't changing, the Doppler shift doesn't change as it gets farther away).
Sound Waves Are Not
Transverse Waves
A floating leaf oscillates up and down two complete cycles in one second as a 10-meter long water wave passes by. What is the wave's speed
Two complete cycles times 10meters. 2*10m=20m/s
A wiggle in time is a
Vibration
An object that completes 10 vibrations in 20 seconds has a frequency of
Vibrations/Seconds = Frequency 10v/20s = 0.5
hat is the relationship among frequency, wavelength, and wave speed?
Wave speed is frequency multiplied by wavelength.
What is meant by the superposition principle?
When two or more waves occupy the same space, wave displacements add at every point.
Can standing waves be formed with transverse waves or longitudinal waves
With both Transverse and Longitudinal waves
Which of these is a transverse wave
a radio wave
Interference is a phenomenon that occurs primarily in
all kinds of waves
The vibrations of a longitudinal wave move
along the direction of wave travel
If a star is moving away from you, the absorption lines in its spectrum will
be redshifted (have wavelengths longer than those of an identical stationary star) Since the star is moving away, the Doppler shift causes the wavelengths to increase.
If you quickly run away from the orchestra at a concert, the frequency of the sound you hear will be
decreased
For the radial speed of an astronomical object to be determined, what MUST the object's spectrum contain?
either absorption or emission lines. (Either absorption lines or emission lines can be used to measure individual wavelengths. These wavelengths are then used to determine the amount of the Doppler shift and the corresponding radial speed.)
What travels in a wave from one location to another is
energy
A shock wave occurs when an aircraft travels
faster than the speed of sound
A shock wave is produced when a wave source moves
faster than the waves it produces
When a sound source approaches a stationary listener, the listener experiences an increase in sound
frequency
In the Doppler effect it is important to distinguish between
frequency and speed
An astronaut on the Mars attaches a small brass ball to a 1.00-m length of string and makes a simple pendulum. She times 12 complete swings in a time of 38.4 seconds. From this measurement she calculates the acceleration due to gravity on the Mars.
g=3.9m/s^2
The frequency of a simple pendulum does Not depend on
its mass
A node is a position of
minimum amplitude
If a hot gas cloud were moving across the sky (neither toward us or away from us), the emission lines would be
neither blueshifted nor redshifted. (Since there is no component to the gas cloud's velocity along a line going from the cloud to the observer, there is no Doppler shift).
Water waves pass by a piece of cork floating on the water that bobs up and down one complete cycle each second. The waves are 2 meters long. What is the speed of the wave
one complete cycle (a frequency) times 2meters long(a wavelength) = 2m/s
The distance traveled by a wave during a single period is
one wavelength
To say that one wave is out of phase with another is to say that the waves are
out of step
The vibrations along a transverse wave move in a direction
perpendicular to the wave
If a star is moving toward you, absorption lines that are in the infrared portion of the electromagnetic spectrum will be
shifted such that they are closer to the visible portion of the spectrum. (The absorption lines are blueshifted, which means the wavelengths become shorter. Since infrared radiation has longer wavelengths than visible light, the absorption lines are shifted toward the visible portion of the spectrum).
If a child swinging to and fro on a playground swing stands up, her time for a to-and-fro swing is
shorter
The pendulum with the greatest frequency is one with the
shortest length
The source of all waves is
something that vibrates
A longitudinal wave is what kind of wave
sound
The Doppler effect is characteristic of
sound waves, water waves and light waves
An aircraft that flies faster than the speed of sound is said to be
supersonic
The compressions and rarefactions in a longitudinal wave travel in
the same direction
If the emission lines in the spectrum of a red star are more strongly blueshifted than those from a yellow star, then the red star is moving
toward us faster than the yellow star.(Since the emission lines are blueshifted, the stars are moving toward us. The red star must be moving faster because its lines are more strongly blueshifted).
A blue shift for light indicates that the light source is moving
toward you
By measuring only an object's Doppler shift, astronomers tend to
underestimate the object's total speed. (Only when the object is moving exactly toward us or exactly away from us does the Doppler shift yield the total velocity of the object).
All waves have in common a
vibrating source
An object that completes 100 vibrations in 5 seconds has a period of
vibrations (v/s =p)= 20s (100 vibrations /5 seconds) = 20 seconds
An object that completes 20 vibrations in 10 seconds has a frequency of
vibrations times seconds. 20 vibrations /10 seconds = 2 Hz
Interference is a property of
water waves, light waves, and sound waves
A wiggle in both space and time is a
wave
Which equation is correct for wave speed
wave speed = frequency x wavelength and wave speed = (1/period) x wavelength
The speed of a wave can be found by multiplying its frequency by its
wavelength
Both a transverse wave and a longitudinal wave have
wavelength, frequency speed, and amplitude
