Tuning fork standing wave in a water pipe

  • Thread starter EF17xx
  • Start date
  • #1
EF17xx
36
0

Homework Statement


IMG_1132.jpg

The question is as follows:
The distance between the two positions of maximum loudness is x
What is the wavelength of the sound emitted by the tuning fork ?
A. x/2
B. x
C. 3x/2
D. 2x

the correct answer is answer D.

Homework Equations


Pipe with two ends open
λn= 2L /n

Pipe with one end open and one end closed
λn= 4L/n

The Attempt at a Solution



At the positions of maximum loudness, there must be an antinode, but the water acts like a closed pipe so there should be a node at the surface of the water. If there is an antinode at the positions of maximum loudness the fundamental frequency would have a wavelength in distance x of λ/2. but that doesn't make sense since there should be a node so now I am confused and also don't understand how to know how many loops there should be.
 

Attachments

  • IMG_1132.jpg
    IMG_1132.jpg
    28.7 KB · Views: 3,250

Answers and Replies

  • #2
kuruman
Science Advisor
Homework Helper
Insights Author
Gold Member
12,601
5,751
The pipe will resonate at the harmonics of the tuning fork frequency. See picture below. When the pipe length is increased by x, what fraction of the wavelength is added to it?
Pipes.png
 

Attachments

  • Pipes.png
    Pipes.png
    17.1 KB · Views: 1,823
  • #3
EF17xx
36
0
The pipe will resonate at the harmonics of the tuning fork frequency. See picture below. When the pipe length is increased by x, what fraction of the wavelength is added to it?
View attachment 222898

I understand now, when the water surface was at the dotted line, there was still a little bit of space above in the pipe, the sound produced was the first harmonic, then when the water moved down another loud sound was heard: The second harmonic and the difference between the first and second harmonic is half a wavelength.
Therefore x=λ/2
and λ= 2x

Thanks
 

Suggested for: Tuning fork standing wave in a water pipe

Replies
5
Views
426
  • Last Post
Replies
1
Views
360
Replies
1
Views
423
  • Last Post
Replies
7
Views
196
Replies
4
Views
345
Replies
4
Views
319
  • Last Post
Replies
6
Views
604
Replies
5
Views
609
Replies
7
Views
401
Replies
15
Views
1K
Top