Physics of Sound Final
I see a flash of lightning strike the ground in the distance during a storm and then I hear the thunder 5 seconds after the flash. Which of the following is closest to the distance from me to the point where the thunder originated?
1,500 meters
The sound speed in a rod of steel is 5900 m/s. If the frequency of a sound transmitted inside this steel rod is 600 Hz, the wavelength of the sound waves in the steel rod will be closest to
10 meters
The concept that multiple vibrational modes can be in existence simultaneously is known as
superposition
For the average human a sound level intensity of 100 dB is a
very loud sound
Two sources of sound across a room from each other have the same frequency. You will observe constructive interference between these waves when
wave pulse minima (troughs) from one sound source reach the listening position at the same time as wave pulse minima (troughs) from the other sound source
Which of the following best describes a sound waveform graph?
A plot of time (x-axis) vs. sound amplitude (y-axis)
What is the purpose of cochlear implants
At a minimum, we want to restore sound audibility/detection (the ability to tell if a sound is present) and ideally, the cochlear implant would allow the person to have speech understanding relying solely on the auditory modality.
Assume there are three metal rods of equal size and shape. One is brass, one is steel, and one is aluminum. The brass is the heaviest, the steel is just slightly lighter, and the aluminum is much lighter. Rank the speed of sound in the rods
It is not possible to determine the speeds without knowing more about the metals
What is the problem in the inner ear that causes vertigo, and occurs when the vestibular nerve is inflamed?
Labyrinthitis
A 9-volt battery is connected to a circuit with a resistor of 30 ohms. What is the current in the circuit
V = IR-->I = V/R = 9/30 = 0.3 amps
When an electric current flows through a coil in a magnetic field, a force is exerted on the coil. This principle is the fundamental mechanism describing the operation of
a dynamic loudspeaker
Standing waves, like those on strings that we created in class, occur when
a traveling wave interferes with an identical traveling wave moving in the opposite direction.
Resonance occurs when an oscillating system (like a mass and spring) vibrates
at its own natural frequency in response to another oscillation.
You can hear music outside an auditorium through an open door even though you don't have a direct line of sight to the musicians playing on stage. This is most likely due to sound waves
being diffracted as they pass through the door
Choose the ordered set of words that best fills in the blanks in the following description of the anatomy of human hearing: Sound waves entering the ear canal cause the _____ to vibrate. These vibrations are transmitted to the _____ by the ______. The ______ translates the vibrations to electrical impulses in the auditory nerve
tympanic membrane, inner ear, ossicles, cochlea
The fact that the human ear responds to a large range of sound intensities leads to the need for a sound intensity level scale in
decibels
The ability to alter the sound levels for different frequencies is known as
equalization
. A sound originates high in the atmosphere, where it's cold. If the sound travels to lower altitude, where it's warmer, the speed of the sound waves will
increase
If the wavelength of a sound increases, but its frequency remains the same, the wave speed must have
increased
A 256 Hz sound source is moving away from you. The frequency you observe is
lower than 256 Hz
The ratio of the loudest sound intensity (Watts per square meter) that humans can stand, to the faintest sound intensity we can hear is closest to
one trillion
Standing sound waves in air confined within a closed pipe will have harmonics that are
only odd integer multiples of the fundamental frequency
When longitudinal waves move through a medium, the particles in the medium oscillate in a direction that is
parallel to the wave direction
For a sound wave moving through a medium, the frequency is
the number of successive air compressions or rarefactions per second passing a point in the medium
The binary number 1101001 is equivalent to the decimal number
105
A piano tuner strikes a 440Hz tuning fork and the A note above middle C on a piano at the same time. She hears a beat frequency of 4 beats per second. As she tightens the piano string, making its pitch higher, the beat frequency decreases. What was the original frequency of the out of tune string in the piano?
436 Hz
A sound with a sound intensity level of 80 dB at 50 Hz has a loudness of
60 phons
The sound spectrogram for a resonating closed pipe will look most like
an odd amount of harmonics
Which of these systems exhibits different harmonic behavior as compared to the other three?
closed pipes
The production of sound waves require
compression of the wave medium, energy, and a physical system that can vibrate
A transducer is a device that
converts mechanical vibrations into electrical signals