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Go to Sound Short Answer Problems (Revised 03-08-06)
Speed of Sound in Air Lab
Purpose :
Materials:
Procedure: (list all relevant steps)
Data Table:
|
Freq. (f) (Hz) |
Harmonic |
Temp. (T) (ºC) |
Column Diameter (d) (m) |
Air
Column length (m) |
Lambda (m) |
Vexp (m/sec) |
Vexp Average (m/sec)
|
Vacc val (V) (m/sec)
|
%E |
|
256 |
1st |
|
|
|
|
|
|
|
|
|
3d |
|
|
|
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|
5th |
|
|
|
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|
320 |
1st |
|
|
|
|
|
|
|
|
|
3d |
|
|
|
||||||
|
5th |
|
|
|
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|
384 |
1st |
|
|
|
|
|
|
|
|
|
3d |
|
|
|
||||||
|
5th |
|
|
|
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|
512 |
1st |
|
|
|
|
|
|
|
|
|
3d |
|
|
|
||||||
|
5th |
|
|
|
Sample Calculations: One complete solution for each of the following must be clearly shown.
Use data from the 512 Hz.tuning fork.
1st harmonic, lambda(1) = 4/1(L + 0.4d)
3d harmonic, lambda(3) = 4/3(L + 0.4d) if possible
5th harmonic, lambda(5) = 4/5(L + 0.4d) if possible
Velocity(EXP) = lambda x frequency
Velocity(ACC VAL) = 331.5 m/sec + 0.6 m/sec (T)
Conclusion:
Answer the following problems on a
separate sheet:
(1) What three important problems were answered by performing this experiment? State the problem as a question, followed by the appropriate answer- including the use of formula(s) and actual values. Your questions must not be those asked below in the conclusion.
(2) What relationship should be apparent among the V(EXP) values for the four tuning forks used? Explain, and substantiate with data – include at least two values + VMATH as reference.
(3) What relationship should be present between V(EXP) average and V(ACC VAL)? Explain, and state specific values. State which variable(s) is/are responsible and which is/are not responsible for the relationship.
(4) What two variables are responsible for your trial having the highest percent error? List them separately. Explain how each affects VEXP, being very specific, and how you might reduce error in each case.
(5) Explain the effect doubling your column's inner diameter would have on the V(EXP) for one of your trials? CAREFUL! Don’t answer intuitively; include formula(s) as your guide.
(6) Why did you not experience a point of audible resonance for the 2nd harmonic region? Diagram.
(7) Why did the tone produced at the two points of resonance for the 384 Hz. tuning fork have the same pitch, even though the length of the air column was very different? Diagrams.
(8) Compare the column length measured for each tuning fork's 1st harmonic. Which tuning fork should have the shortest column length for this harmonic? Explain why. If you have a measurement less than this value for any of the other tuning forks, what does this mean?
Sources of Lab Error: (Not required. Error was discussed in #4 in the conclusion)
Practice Problems: (Any two short answer problems)