Final answer:
If the tube originally has a fundamental frequency of 440 Hz when open at both ends, upon closing one end, the fundamental frequency will decrease. This is because the fundamental wavelength for a tube open at one end is four times its length, leading to a lower fundamental frequency of 250 Hz.
Step-by-step explanation:
When considering a tube open at both ends, the fundamental frequency is determined by the length of the tube and the speed of sound within it. If the tube has a fundamental frequency of 440 Hz when open at both ends, and it is then changed to being open at one end and closed at the other, the fundamental frequency would be different. The wavelength for the fundamental of a tube open at one end is four times its length (4L), while for an open tube, it is twice its length (2L). This means an open tube resonates at a higher fundamental frequency than when it is closed at one end.
Using this information, if a tube open at both ends has a fundamental frequency of 500 Hz, the fundamental frequency when one end is closed is lower because the wavelength of the standing wave is longer. The new wavelength will be four times the length of the tube, not two, and so the fundamental frequency will be halved. Therefore, if one end of the tube is closed, the new fundamental frequency would be 250 Hz.