For a Diffraction Horn Loudspeaker, the Sound Emerges Through a Rectangular

Multiple Choice

For a diffraction horn loudspeaker, the sound emerges through a rectangular opening. The width of a diffraction horn is 0.14 m. If the speed of sound in air is 343 m/s, at what frequency is the diffraction angle $\theta$ equal to 35°?

A) 3300 Hz
B) 4300 Hz
C) 6300 Hz
D) 7700 Hz
E) 9200 Hz