High School Ultrasonic wave and regular sound wave

  • Thread starter Thread starter Hesh123
  • Start date Start date
Click For Summary
The speed of sound in gases is influenced by temperature and is described by the formula v = √(γP/ρ), where γ is the specific heat ratio. This formula applies to all sound waves, including ultrasonic waves, as they are not fundamentally different in speed from normal sound waves. The distinction between normal and ultrasonic sound is based on frequency, not speed. In ideal gases, the speed of sound remains consistent across frequencies, with only minor variations in real gases. Therefore, the teacher's assertion about different formulas for normal and ultrasonic sound speed lacks context and is incorrect.
Hesh123
Messages
1
Reaction score
0
Does the speed of ultrasonic waves differ from the normal sound wave speed?
my teacher said that for normal sound wave speed v= √(γP/ρ)and for ultrasonic sound speed v= √(P/ρ) is he wrong?
 
Physics news on Phys.org
Welcome to PF.

In air, water, or in solids?
All low-amplitude sound waves propagate at the same speed, independent of frequency.

In a gas, the speed of sound is dependent on temperature. Large amplitude sound waves, where the pressure wave can change the instantaneous air temperature, can be distorted, or become shock waves.
 
Reply
  • Like
Likes Hesh123 and Lord Jestocost
I think gamma here is the ratio of the adiabatic to isothermal values for specific heat capacity. I will try to find out if there is a change as the frequency increases.
 
Hesh123 said:
is he wrong?
Yes, unless some context is missing. Ultrasound is just a name related to human hearing specifics. The formula without gamma was proposed by Newton and was latter corrected by Laplace by adding the gamma factor. The compression of air in a sound wave is better described as adiabatic rather than isothermal (as Newton assumed). The formula assumes an ideal gas, of course. In real gases there is a weak dependence of temperature and even weaker dependence on frequency.
 
Reply
  • Informative
  • Agree
Likes Hesh123 and berkeman
Hesh123 said:
Does the speed of ultrasonic waves differ from the normal sound wave speed?
my teacher said that for normal sound wave speed v= √(γP/ρ)and for ultrasonic sound speed v= √(P/ρ) is he wrong?
You can see from the reply by nasu #4 that your first formula applies at all frequencies.
 

Thread 'Reference frames, center of rotation, etc'

Topic about reference frames, center of rotation, postion of origin etc Comoving ref. frame is frame that is attached to moving object, does that mean, in that frame translation and rotation of object is zero, because origin and axes(x,y,z) are fixed to object? Is it same if you place origin of frame at object center of mass or at object tail? What type of comoving frame exist? What is lab frame? If we talk about center of rotation do we always need to specified from what frame we observe?
View full post »

Similar threads

Undergrad How fast does a blastwave travel?
  • · Replies 236 ·
8
Replies
236
Views
15K
Undergrad How does sound reflect from an interface at an angle?
  • · Replies 17 ·
Replies
17
Views
2K
Difference between Ultrasonic waves and sound waves.
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Some questions regarding Acoustic wave reflection
  • · Replies 11 ·
Replies
11
Views
1K
Can the Speed of Sound Be Measured Using Frequency and Time Delay Data?
  • · Replies 23 ·
Replies
23
Views
3K
Are the Frequencies of a Plucked String and the Corresponding Sound Wave Equal?
  • · Replies 1 ·
Replies
1
Views
1K
Speed of Sound in Different Mediums
  • · Replies 2 ·
Replies
2
Views
2K
Supersonic wave and distance calculation
  • · Replies 8 ·
Replies
8
Views
3K
Undergrad Does two-slit sound-wave interference pattern return to original form?
  • · Replies 10 ·
Replies
10
Views
2K
I want to create an ultrasonic generator amplifier w/ MOSFET
  • · Replies 5 ·
Replies
5
Views
5K