7! Open You see that the right end of an organ pipe is open, but you don't know whether the left end is open or closed. You run air through the pipe and discover that one ofthe resonant frequencies is 300 Hz, and that the next higher one is 420 Hz. (Remember that open ends of a pipe act like nodes of pressure, while closed ends act like antinodes of pressure.) (a) Is the left end of the pipe open or closed? (b) How long is the pipe? (Recall that the speed of sound in air is 343 m/s.) (c) Sketch a graph of the air pressure as a function of position along the interior of the pipe for the 300 Hz standing wave. Your graph should show the locations of the nodes and the antinodes