Questions tagged [ultrasound]
32 questions
21
votes
6 answers
How can ultrasound hurt human ears if it is above audible range?
Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. Then ultrasound is above 20 kHz
Occupational exposure to ultrasound in excess of 120 dB may lead to
hearing loss.
Source
How can ultrasound hurt human ears if it is above…
William Houston
- 229
6
votes
2 answers
Do humans use the doppler effect to localize sources of sound?
Consider a source of sound such as a person speaking or a party of people which makes a continual drone sound of the the same frequency. If a human shakes their head side-to-side with sufficient angular speed, they are in effect obtaining different…
kbakshi314
- 2,430
2
votes
2 answers
If the frequency of a sound wave doubles, does its energy quadruple?
Or does it double?
What about its 'intensity' or power?
Acoustic physics is confusing me more than electromagnetic waves did....
Is there a single list somewhere of the equation(s) relating to sound?
Kurt Hikes
- 4,767
- 3
- 19
- 41
1
vote
1 answer
Why is an ultrasonic transducer able to send energy into a tank without an opposing surface?
The diagram shows an ultrasonic transducer stuck to the bottom of an ultrasonic cleaning tank full of water/detergent. It's not supported at the opposing end - just hanging off the bottom of the tank. The piezoelectrics vibrate, causing the…
Oliver Walters
- 167
1
vote
1 answer
Doppler effect on bistatic system with offset sensors
I am wondering if there would be any induced doppler-effects for a setup where a object is moving in a straight line but the emitting and receiving sensor are offset. The equation for the bistatic doppler shift…
iato
- 145
1
vote
0 answers
Ultrasonic diffraction
When ultrasonic is applied to a liquid it creates an acoustic grating in which some part have more refractive index and some part have low refractive index. When light is passed through this grating it only passes through the rarer part of the…
1
vote
1 answer
Is low frequency sound slower (in air)?
Does sound in air experience dispersion? In other words, is the group velocity of sound higher for higher frequencies or the other way round? Is this difference substantial enough to be noticed/heard?
This is an attempt to put on more serious…
Roger V.
- 68,984
1
vote
1 answer
How sparse does air have to get before the speed of sound slows dramatically? Or ceases altogether?
Supposedly, at low altitudes, the increase in the speed of sound due to the increased pressure of air (and therefore, compressibility?) almost exactly cancels out the decrease in sound velocity due to increased density....
But the temperature goes…
Kurt Hikes
- 4,767
- 3
- 19
- 41
1
vote
2 answers
In ultrasound, why doesn't the reflected sound gets reflected again on its way back?
Consider the diagram below illustrating how A-scans work, why doesn't some of the reflected sound on its way back at the red circle interface reflect again (thereby reducing the signal intensity recorded at the green arrow)?
Bøbby Leung
- 827
0
votes
3 answers
Eliminating sound vibrations by using destructive interference for sound waves
Can you eliminate sound vibration (when either it is audible sound, ultrasound or infrasound) by creating a destructive interference, but when both sources are in opposite sides?
Say, you have one audio speaker playing in one corner of the room and…
lement
- 1
0
votes
1 answer
Reflection of sound wave passing through gas to solid and through solid to gas
Why following are true in both cases?.
1- Ultrasound passing through a metal block(solid medium) will not pass through a cavity (air medium) inside the block.
I got some explanation as speed of sound is less in air so air resist the moving wave…
Level1
- 101
0
votes
0 answers
Can ultrasounds generate lift?
Imagine a plate, the bottom side is flat and the top has dimples (or other structures that increase surface area)
If we vibrate it ultrasonically left and right wouldn’t it experience lift because of different air pressures on each side due to…
Pedro
- 119
0
votes
2 answers
Does ultrasonic sound travel the same way "normal sound", which human can hear, does?
Please excuse my terminologies if they are not accurate as I am not an expert in physics.
For the sake of my question, if I may, I would simplistically call "ultrasonic sound" the sound that human cannot hear, and only some animals such as…
0
votes
1 answer
How would one calculate the electric field produced by a piezoelectric device in response to a sound wave?
So the governing equations of piezoelectricity are:
Where E is the electric field, D is the displacement field, S is the strain, and T is the stress. Say I have a piezoelectric device where the mechanical force on the device is given by a sound…
NaP
- 23
0
votes
1 answer
Measuring longitudinal and transverse (shear) waves speed in glass substrates
Let say I have a $500-1000 \ \mathrm{microns}$ thick glass substrate.
How can I experimentally measure the longitudinal and transverse wave speed in this substrate?
I can either attach a piezo disk to one side of the glass, send a pulse and detect…
