Two speakers face each other, and they each emit a sound of wavelength λ. One speaker is 180∘ out of phase with respect to the other. If we separate the speakers by a distance 1.5λ, how far from the left-most speaker should we place a microphone in order to pick up the loudest sound? Ignore reflections from nearby surfaces. Select all that apply.. .
a) 1/4λ.
b) λ. c
) 0λ.
d) 1/2 λ. e) 3/4 λ.