In the figure, S is a small loudspeaker driven by an audio oscillator and amplifier, adjustable in frequency from 500 to 3000 Hz only. Tube D is a piece of cylindrical sheet-metal pipe 50.1 cm long and open at both ends. (a) If the speed of sound in air is 344 m/s at the existing temperature, at how many frequencies will a resonance occur in the pipe when the frequency emitted by the speaker is varied from 500 Hz to 3000 Hz? (b) What is the lowest resonant frequency in the given interval? (a) Number Units No units (b) Number Units