In its search for flying insects, a bat uses an echolocating system based on pulses of high frequency
sound. These pulses are 2.0 ms in duration, have a frequency of 50 kHz, and an intensity level of 100
dB at 1.0 m from the bat’s mouth. Assume the bat produces acoustic waves in a cone with a total
angle of 30degree.
(a) What is the acoustic power of each pulse?
(b) How much acoustic energy is there in each pulse?
(c) What is the intensity and intensity level at a conical surface centered on the bat with radius equal to 5.0 m?
(d) A June bug is located 5.0 m from the bat. The effective cross-sectional area of the insect is 10
mm2. How much of the acoustic power emitted by the bat is intercepted by the insect?
(e) Assume all the acoustic power intercepted by the June bug goes into the reflected wave which is
hemispherical. What is the intensity and intensity level of the reflected wave at the bat’s ears?
1 answer