試題詳解

16. Bats can detect small objects such as insects that are of a size on the order of a waveleng a chirp at a frequency of 60 kHz and the speed of soundwaves in air is 330 m/s smallest size insect they can detect?
(A) 1.5 mm
(B) 3.5 mm
(C) 5.5 mm
(D) 7.5 mm
(E) 9.8 mm