The following statements refer to properties of standing sound waves in tubes. O
ID: 1787468 • Letter: T
Question
The following statements refer to properties of standing sound waves in tubes. One of the following statements is incorrect. Select it.
a) If a tube is open at both ends, the sound wave at the fundamental frequency has two antinodes.
b) If a tube is closed at one end and open at the other end, the second harmonic frequency is three times the fundamental frequency.
c) If a tube is open at both ends, the third harmonic frequency is three times the fundamental frequency.
d) The fundamental frequency is the same for a tube closed at both ends as for a tube open at both ends.
e) Halving the length of the tube halves the fundamental frequency.
Explanation / Answer
(a) A tube with vibrating air that is open at both ends has antinodes at both ends. The fundamental frequency is
f = v/2L
Given statement is correct.
(b)there is no second harmonic for a closed-end air column
Given statement is incorrect.
(c)If a tube is open at both ends, the third harmonic frequency is three times the fundamental frequency.
n3 = 3 ( n1)
Given statement is correct
(d) Fundamental frequency for open ened tube is n1 = v /2L and for closed ended is n1 = v/4L
Thus, the given statement is incorrect.
(e) Fundamantal frequency is inversely proportional to length
Half the length, double its frequency.
Thus, the given statement is incorrect.