00:01
Number 66.
00:03
It's about a empty bottle that has a fundamental wavelength of 0 .88 meters.
00:13
So an empty bottle, that's just a tube that's closed at one end, open at one end, closed at the other.
00:20
And they want to know what is the length of the bottle.
00:23
And then also what is the frequency of the third harmonic.
00:26
So here's my bottle.
00:27
So when i have the fundamental, that's when there's a note at one end, there's an antinode at the other.
00:33
So the length of this tube l is one fourth of a wave -length.
00:41
And i know the wavelength is 0 .88.
00:49
That's a 4 .8.
00:55
So the length of this bottle must be 0 .22 meters.
01:09
So now when i have the third harmonic, that's when i still have a node at one end and ant to note the other...