Hearing is the ability to detect _______ and performed by ____. The human ear can only be sensitive in the range of frequency of ___ Hz. to ___ Hz.
举一反三
- Hearing is the ability performed by (______) to detect (______).
- An open pipe of air supports standing waves at frequencies of 300 Hz and 400 Hz. There are no other frequencies between these two. What is the frequency of the second harmonic of this tube? A: 100 Hz B: 200 Hz C: 400 Hz D: 600 Hz
- 超声波的频率大于___Hz，次声波的频率小于___Hz．
- Calculate the low frequency break point due to the capacitor CS for this BJT amplifier. [img=401x275]1803966add25148.png[/img] A: fLs = [img=98x43]1803966ae83ee52.png[/img] = 280.25 Hz B: fLs =[img=130x43]1803966af50fda0.png[/img] = 30.6 Hz C: fLs = [img=96x43]1803966aff1bc04.png[/img] = 5585.4 Hz. D: fLs = [img=132x43]1803966b0d87e79.png[/img] = 4.269 Hz.
- 一机车汽笛频率为750 Hz,机车以时速90公里远离静止的观察者.观察者听到的声音的频率是(设空气中声速为340 m/s). A: 810 Hz. B: 699 Hz. C: 805 Hz. D: 593 Hz.