Question

For an ideal resonance tube an antinode occurs at the open end of the tube. What property of real resonance tubes slightly alters the position of this antinode

Answer 1

Note that for real resonance tube the point at which the upper antinode occurs is just outside the end of resonance tube. This location depends upon the diameter of the tube. This is the reason why there is slight change of position of the antinode in case of real resonance tubes. This is called end correction (e). For resonance tubes open at one end and closed at other,

e = 0.3d

(where d is diameter of the tube)

and for pipe open at both ends,

e = 0.6d.