WAEC Physics 2023 Paper

Concept:In an open tube, the first overtone corresponds to one complete wavelength inside the tube.Explanation:For an open tube, both ends are free to vibrate, so both ends are antinodes.For the fundamental mode, the length is $l = \frac{\lambda}{2}$.For the first overtone, the wavelength decreases so that $l = \lambda$.Therefore, the correct diagram must show a full wavelength in the tube.This full-wave pattern has antinodes at both ends and at the middle, with nodes at the $\frac{1}{4}$ and $\frac{3}{4}$ positions.So, the diagram showing $l = \lambda$ in an open pipe is the correct one.Answer:Choose the diagram that shows the open tube containing one full wavelength, i.e., $l = \lambda$.