MT 1 Flashcards
For a transverse wave on a string is the wave speed the same as the speed of any particle of the string?
A.Yes, the wave speed is the same as the speed of the particles
B.No, the wave speed is different from the speed of the particles
The wave speed is different from its particles, the wave propagates at a constant speed along some direction, while particles oscillate in perpendicular direction.
The four strings on a violin have different thicknesses but all are under approximately the same tension. Do waves travel faster on the thick or the thin strings?
A.Waves travel faster on the thick strings
B.Waves travel faster on the thin strings
C.Waves have the same speed on all strings
The lighter the string, the faster the speed, since v=(T/m)1/2
If you stretch a rubber band and pluck it, you hear a (somewhat) musical tone. How does the frequency of this tone change as you stretch the rubber band further?
A.The frequency increases
B.The frequency decreases
C.The frequency does not change.
The frequency will increase with tension because v=(T/m)1/2, and f=v/l
A musical interval of an octave corresponds to a factor of 2 in frequency. By what factor must the tension in a guitar string be increased to raise its pitch one octave.
A.By a factor of 2
B.By a factor of 4
C.By a factor of 8
because frequency is proportional to square root of tension, raising it by a factor of 4 will raise the frequency by a factor of 2
When sound travels from air to water
A. Frequency changes, wavelength and speed are the same
B. Wavelength changes, frequency and speed are the same
C. Both wavelength and speed change, the frequency is the same
C. Both wavelength and speed change, the frequency is the same
The hero of a western movie listens for an oncoming train by putting his ear to the track. Does this method give an earlier warning of the approach of the train than just listening in the usual way?
A. No, the hero just wants to look cool.
B. No, since the speed of sound in air is larger than the speed of sound in metallic track
C. Yes, because the speed of sound in metallic track is larger than that in the air
C. Yes, because the speed of sound in metallic track is larger than that in the air
When both ends of the organ pipe are open, a standing air wave is formed with
A. Displacement nodes at both ends.
B. Pressure fluctuation nodes at both ends.
C. Pressure fluctuation node at one end and displacement node at another.
B. Pressure fluctuation nodes at both ends.
When one end of the organ pipe is open and another one is closed, a maximum wavelength of the standing air wave is
A. The same as the length of the pipe
B. Twice as much as the length of the pipe
C. Four times as much as the length of the pipe
C. Four times as much as the length of the pipe
A sound source and a listener are both at rest but a strong wind is blowing from the source towards the listener. Is there a Doppler effect?
A. Yes
B. No.
B. No.
The law of reflection states that the angle of incident and angle of reflected rays
A. are the same
B. are related to each other as nasinθa=nbsinθb
C. are related to each other as na/sinθa=nb/sinθb
A. are the same
When light passes through a material, its speed compared to the light velocity in vacuum
A. Decreases
B. Increases
C. Does not change
A. Decreases
Why when you put a stick into a glass of water it appears bended?
A. Because reflected rays from the stick refract at the surface water-air
B. Because the water acts as a converging lens
C. Because the light disperses when passing the surface water-air
A. Because reflected rays from the stick refract at the surface water-air
A ray parallel to the axis of a concave mirror
- Is reflected along the radius thru the center of the curvature of the mirror
- After reflection passes through the focal point
- Is reflected also parallel to the axis
2.After reflection passes through the focal point
A ray passing thru a focal point of a thin converging lens 1.Is refracted parallel to the lens axis
- Does not deviate appreciably
- Refracts to pass through the second focal point
1.Is refracted parallel to the lens axis
Any image formed by a plane mirror is always
Virtual Erect
An image of a coin embedded in the crystal ball is A.Virtual
B. Real
A.Virtual
A sound source and a listener are both at rest but a strong wind is blowing from the source towards the listener. Compared to the source frequency the listener will hear the sound of?
the same frequency
When you pluck a guitar string the wave produced can be described as?
A standing transverse wave (because the guitar string is fixed at both ends)
When do waves occur
when a system is disturbed from equilibrium and the disturbance travels
what happens as a wave travels
it carries energy
mechanical waves
waves that travel in a medium like sound. Particles that make up the medium undergo displacement.
sinusoidal wave
wave pattern is a repeating cos or sin fxn
interference
when oppositely directed waves overlap
electromagnetic wave
can travel in empty space (Without a medium)
ex)light, radio waves, etc
transverse wave
displacement of the particles that make up the medium is perpendicular to the direction of travel of the wave along the medium
longitudinal waves
displacements of the particles that make up the medium are parallel to the direction of travel of the wave along the medium
what do waves transport
energy, not matter
periodic waves
each particle in the string undergoes periodic motion as the wave travels
sinusoidal waves
periodic waves with simple harmonic motion
wavelength
distance from 1 crest to the next
amplitude
height of the crest above the equilibrium level
power
rate of doing work
intensity
waves on a string carry energy in 1D, but other types of waves carry energy across all 3 dimensions. This is where intensity comes into play.
when a wave strikes the boundaries of its medium
all or part of the wave is reflected
standing wave
doesn’t appear to move at all
sound
longitudinal wave in a medium
doppler effect
when listener hears a frequency different from the one emitted by the source
What can sound travel through?
gas, liquid, solid
ultrasonic
frequencies that are above the audible range
infrasonic
frequencies that are below the audible range
dichroism
something is absorbed too strongly
