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16. The speed of sound in a classroom is 343 m/s. a) A tuning fork of frequency 512 Hz is struck. What length of open air tube is required to create a resonant sound at the 1 st harmonic? 2 marks b) For the same tube, what tuning fork frequency is needed to generate a resonant tone at the 3"d harmonic? 2 marks c) In the same classroom, what is the lowest resonant frequency for a closed air tube of length 45.0 cm