Unit 12 Concepts
The approximate range of human hearing is
20 Hz to 20,000 Hz.
The wavelength of the fundamental frequency of a vibrating string of length L is
2L
Consider an open pipe of length L. What are the wavelengths of the three lowest tones produced by this pipe?
2L, L, 2L/3
The speed of sound in air at normal temperatures is about ____ m/sec.
340
The lowest tone to resonate in an open pipe of length L is 200 Hz. Which one of the following frequencies will not resonate in the same pipe?
900Hz
_________ does not affect the pitch of the note played on a musical string?
Color of the string
a loud noise created by a pressure wave that follows an object moving faster than the speed of sound
Sonic boom
An open pipe of length L is resonating at its fundamental frequency.
The wavelength is 2L and there is a displacement node at the pipe's midpoint.
Large horns such as tubas produce sounds with long wavelengths while flutes produce sounds with short wavelengths because:
The wavelength of sound produced is directly proportional to the size of the instrument
Sound waves cannot travel in
a vacuum
When an air column vibrates in a pipe that is open at both ends,
all harmonics are present
The Doppler effect occurs with
all waves
The loudness of a musical sound is a measure of the sound wave's
amplitude
In a resonating pipe which is open at both ends, there
are displacement antinodes at each end.
At a concert the oboe is playing a long steady note as you walk away from the stage at an accelerating velocity toward the rest room. The pitch of the sound that you hear, is
constantly decreasing
Due to the Doppler effect, the pitch of the siren of a fire truck moving away from you:
decreases
_________ factor that does not affect the pitch of a note played on a musical pipe
diameter of the pipe
A Doppler effect occurs when a source of sound moves
either towards you or away from you
Pitch depends on the ____ of a sound wave.
frequency
A train moves down the track toward an observer. The sound from the train, as heard by the observer, is ____ the sound heard by a passenger on the train.
higher in pitch than
In a resonating pipe which is open at one end and closed at the other, there
is a displacement node at the closed end and a displacement antinode at the open end.
Sound waves are
longitudinal waves
As a source of continuous sound approaches a constant speed, you will NOT be aware of an apparent increasing of its
loudness, frequency, and wavelength
A light source that moves towards an observer at very high speeds (more than half the speed of light) will appear
more blue
A light source that moves away from an observer at very high speeds (more than half the speed of light) will appear
more red
When an air column vibrates in a pipe that is closed at one end,
only odd harmonics are present
The highness or lowness of a sound is perceived as
pitch
The Doppler effect is characteristic of
sound, light, and water waves
Sound travels faster in
steel
The term applied to objects that travel at speeds exceeding the normal speed of sound in air is:
supersonic
The speed of a sound wave in air depends on
the air temperature
If you are on a train, how will the pitch of the train's whistle sound to you as the train moves?
the pitch will not change
True or False? A sound source of high FREQUENCY emits a high PITCH?
true
The Doppler shift explains
why the siren on a police car changes its pitch as it races past us