I Pracownia Zakładu Fizyki PL.
Nazwisko i imię |
Grupa ED 2.5 |
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Data wyk. Ćwicz 02.03.98 |
Numer ćwicz. 1 |
Temat ćwiczenia : Wyznaczenie prędkości fali głosowej metodą rezonansu |
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Zaliczenie |
Ocena |
Data |
Podpis
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1.Zasada pomiaru
Wyznaczenia prędkości fali głosowej dokonuje się przy wykorzystaniu zjawiska powstawania fali stojącej (rezonansu) słupa powietrza w rurze wywołanej drganiem kamertonu. Drgający kamerton jest źródłem fali, która ulega odbiciu od granicy ośrodków (woda) i interferuje z falą padająca tworząc falę stojącą. Regulując długością słupa powietrza w rurze (poprzez zmianę poziomu wody) można doprowadzić do wzbudzenia drgań własnych (rezonansu), co objawia się zwiększeniem siły głosu. Fala stojąca ma wtedy węzeł na poziomie wody, a strzałkę u wylotu rury. Jeżeli będziemy zmieniali wysokość słupa powietrza wypuszczając z rury wodę będziemy obserwowali powstawanie rezonansu za każdym razem, gdy wysokość słupa powietrza będzie równa nieparzystej wielokrotności ćwiartki długości fali dźwiękowej.
gdzie n = 0,1,2,3...
Mierząc odległość pomiędzy dwoma kolejnymi wzmocnieniami znajdujemy połowę długości fali.
Znając częstotliwość kamertonu możemy obliczyć prędkość rozchodzenia się fali głosowej w powietrzu o temperaturze 273 K ze wzoru:
Podstawiając za λ wartość obliczoną z różnicy poziomów l2-l1 otrzymujemy wzór końcowy:
2.wyniki pomiarów
Lp. |
l1 |
l2 |
|
|
ν |
T |
|
|
m |
m |
m |
m |
1/s |
K |
m/s |
1 |
0,17 |
0,563 |
|
|
|
|
|
2 |
0,167 |
0,559 |
|
|
|
|
|
3 |
0,166 |
0,562 |
|
|
|
|
|
4 |
0,165 |
0,560 |
|
|
|
|
|
5 |
0,164 |
0,563 |
0,166 |
0,162 |
440 |
298 |
333,5 |
6 |
0,164 |
0,566 |
|
|
|
|
|
7 |
0,165 |
0,561 |
|
|
|
|
|
8 |
0,164 |
0,563 |
|
|
|
|
|
9 |
0,165 |
0,562 |
|
|
|
|
|
10 |
0,167 |
0,565 |
|
|
|
|
|
3.Obliczenia
4.Dyskusja błędów
r=l1-l2 |
ri2 |
4*10-3 |
16*10-6 |
1*10-3 |
1*10-6 |
0*10-3 |
0*10-6 |
-1*10-3 |
1*10-6 |
-2*10-3 |
4*10-6 |
-2*10-3 |
4*10-6 |
-1*10-3 |
1*10-6 |
-2*10-3 |
4*10-6 |
1*10-3 |
1*10-6 |
-1*10-3 |
1*10-6 |
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