試題詳解

41. If middle C (262 Hz) and C^# (277 Hz) are played together, it would cause interference beats. What the beat frequency would be if each is played one octave lower (each frequency reduced by a factor of 2)?
(A) 30 Hz
(B) 15 Hz
(C) 7.5 Hz
(D) 3.75 Hz
(E) None of the above.