Physics chapter 6 waves
When an oscillator is driven in resonance,
. there is maximum energy transfer
A radar pulse returns 9.0 × 10-4 s after it was sent out and reflected by an object. What is the separation distance of the radar source and the object?
1.4 × 105 m
frequency =
1/period
which of the following sound frequencies could be heard by the human ear
10,000 Hz
a sound of 30dB is how many times louder than the threshold of hearing
1000
A series of ocean waves, each 24.0 m from crest to crest and moving past an observer at a rate of 6.0 waves per second, has what speed?
144 m/s
what is the frequency range of human hearing?
20 Hz - 20 kHz
the ultrasonic region is above the sound frequency of
20khz
to double the loudness or sound intensity a dB difference of_________ is needed
3
how fast do electromagnetic waves travel in a vacuum?
3.00x10^8 m/s
Which of the following sound frequencies lie(s) outside the audible range?
47khz
What is the frequency, in hertz, of a sound wave (v = 340 m/s) with a wavelength of 68 m?
5 Hz
Which of the following sound frequencies lie(s) in the audible range?
5 kHz
Which of the following radiations has the longest wavelength?
Infrared
Light can travel to Earth from a distant star, but sound cannot. Why is this?
Light is an electromagnetic wave, and sound requires a medium.
Which of the following radiations has the greatest frequency?
X-rays
if an astronomical light source were to be moving towards us what would we observe
a blueshift
What is necessary for a jet aircraft to generate a sonic boom?
a jet aircraft with a speed greater than speed of sound in air
Standing waves can be set up in a string when two waves that are
a. of the same frequency and amplitude, but are opposite in direction of travel, meet each other
the energy of a wave is related to the square of which of the following?
amplitude
Wave frequency is inversely proportional to
amplitude. period. wave velocity
a moving observer approaches a stationary sound source what do they hear
an increase in frequency
Resonance occurs when
an object having a certain natural frequency is set in vibration by a second object vibrating at that frequency
What causes waves and how do they propagate?
an originating disturbance, energy is transmitted from one particle to another in a medium as a wave propagates outward
how is electromagnetic spectrum arranged
arranged in sequences of wave frequencies or wavelengths
What does resonance mean in terms of a systems energy?
at resonance frequencies there is a maximum energy transfer to a system
A sound with a frequency of 1000 Hz is in the ______________ region of the sound spectrum.
audible
what is the speed of light in a vacuum
c=3.00 x 10^8 m/s
electromagnetic spectrum
different wavelength regions are given names
The major difference between transverse and longitudinal waves is the
direction of the particle displacement with respect to the direction of wave motion.
light waves are ______ waves
electromagnetic
Wave amplitude is related to
energy
waves involve the propagation of
energy
Wave period is the reciprocal of
frequency
A train sounding its horn is moving toward an observer. The pitch of the horn's sound relative to its normal pitch is
higher
resonace occurs at _____ frequencies
higher
is matter propagated by waves?
in general energy is propagated by waves not matter.
An observer moving toward a stationary sound source hears a(n) ___ _____ in
increase
decibels are used to measure the sound property of
intensity
sound
is a propagation of longitudinal waves through matter
in a vacuum electromagnetic waves travel at the speed of
light
sound waves are _______ waves
longitudinal
what is the distinguishing difference between longitudinal and transverse waves?
longitudinal and transverse waves are are distinguished in terms of a particle motion and wave velocity. they are paralleel in longitudinal waves and perpendicular (90 degrees) in transverse waves
A disturbance in particle motion parallel to the wave velocity is called
longitudinal wave
a wave with particle oscillation parallel to the direction of propagation is
longitudinal wave
amplitude
maximum displacement of any part of wave from its equilibrium position
Are particles in a standing wave really "standing or stationary?
no opposite moving particles continually interfere, but the nodes are the only stationary points
Hertz
one cycle per second
dB
one tenth of a Bel
wave velocity and particle motion are _______ in transverse waves
perpendicular
if a piece of ribbon were tied to a stretched string were carrying a transverse wave , then how is the ribbon observed to oscillate
perpendicular to wave direction
the speed of sound is greatest in
solids
ultrasound
sound waves with frequencies greater than 20,000 Hz
which of the following properties does not change in the Doppler effect
speed
which of the following occurs when a stretched string is shaken at one of its natural frequencies
standing waves,resonance, maximum energy transfer
standing waves
stationary waves
speed of light
sun travels through a vacuum of space before reaching earth
What is the Doppler effect?
the apparent change in frequency of the moving force
when the dB doubles does the sound instantly double?
the dB scale is nonlinear and an increase of 3dB per second doubles sound intensity
frequency
the number of oscillation or cycles that occur in a period of time
longitudinal wave
the particle motion and the wave velocity are parallel to each other
transverse wave
the particle motion is perpendicular
intensity
the rate of sound energy transfer through a given area
period
the time it takes the wave to travel the distance of one wavelength
The Doppler effect is observed only when
there is relative motion between the source of a wave and an observer
How is the frequency and period related
they are inversely related
which of the following has frequencies greater than the visible region in the electromagnetic spectrum
ultraviolet
Light waves travel fastest in
vacuum
For a wave with a constant speed, the smaller the period, the smaller (or shorter) its
wavelength
the distance from one wave crest to an adjacent wave crest is called
wavelength
wave speed is equal to frequency times
wavelength
The region of the electromagnetic spectrum with frequencies just greater than those in the ultraviolet region is the ______________ region.
x rays
The region of the electromagnetic spectrum with wavelengths just less than those in the ultraviolet region is the ______________ region
x rays