Two loudspeakers are placed on a wall 2.05 m apart. A listener stands 3.20 m from the wall directly in front of one of the speakers. The speakers are being driven by a single oscillator at a frequency of 282 Hz. What is the phase difference between the two waves when they reach the observer? Take the speed of sound in air to be 343 m/s.
What is the frequency closest to 282 Hz to which the oscillator may be adjusted such that the observer hears minimal sound?