Pre-Lab: Resonance in an Air Column         Name:

 

Double Open End Tube

Single Open End Tube

 
  1. (½)  In a tube with both ends open, the position of the first resonance occurs
    1. l/4
    2. l/2
    3. 3l/4
    4. l

 

  1. (½)  The position of the second resonance occurs another ____ after the first resonance.
    1. l/4
    2. l/2
    3. 3l/4
    4. l

 

  1. (½) Sketch in the wavelength for the first resonance in a double open-ended tube as in Figure 1 of your lab manual.

 

      

  1. (½)  In a tube with a single end open, the position of the first resonance occurs
    1. l/4
    2. l/2
    3. 3l/4
    4. l

 

  1. (½)  The position of the second resonance of the single open ended tube occurs another ____ after the first resonance.
    1. l/4
    2. l/2
    3. 3l/4
    4. l

 

  1. (½) Sketch in the wavelength for the first resonance in a single open-ended tube.

 

        

Click here if having difficulty

 

v = f l

l = v (1/f)

l = v  (T)  + 0

y = m   x   + b

 

7.  (2) Analyze and graph the following data to calculate the speed of sound.

Antinode positions

285 Hz HzH;lkasjdf;asdlkf

375 Hz

490 Hz

x1 (cm)

29.3

0.3

13.8

x2 (cm)

89.5

46.2

49.1

x3 (cm)

 

91.5

83.9

xave internodal

 

 

 

l (cm)

 

 

 

T(sec)

 

 

 

 

Note:      The above data is valid for double opened tubes.  The gray outer tubes are 91.0 cm.  The below sketches are valid for the 490 Hz turning fork.  The actual resonance positions are 91 + 13.8, 91 + 49.1, and 91 + 83.9.    In today’s lab you are ONLY to record the numbers on the inner tube as displayed in the table.

 

 

                 

 

How to calc average internodal distances?   [(x2 – x1) + (x3 – x2) + (x4 – x3)] / n   

In the above case, we have n =2, so [(x2 – x1) + (x3 – x2)] / n    = [(49.1 – 13.8) + (83.9 – 49.1] / 2