Which harmonic frequencies can be detected in a tube closed at one end whose fundamental frequency is 200 Hz?
200 Hz
300 Hz
400 hz
600 Hz
1000 Hz
It's a select multiple and I said the last three which was wrong.
2 answers
You were guessing. wavelength has to be a odd multiple of 200. If you dont get that, there are two of them
node at closed end, max at the open end.
Draw the picture.
first boom at 1/4 of wavelength = length of tube L
say the speed of sound is c
c = wavelength /period = wavelength* f
now we are told that 1/4 wavelength is L
c = 4 L*200 = 800 L
so the next time we have a node at the closed and a max at the open end is when
wavelength = (4/3)L
c = (4/3)L*f = 800 L
f = 800 *3/4 = 600 Hz <-------
the next time is when
5/4 wavelength = L
c = (4/5)L*f= 800 L
f = 1000 Hz <--------
200, 600, 1000
Draw the picture.
first boom at 1/4 of wavelength = length of tube L
say the speed of sound is c
c = wavelength /period = wavelength* f
now we are told that 1/4 wavelength is L
c = 4 L*200 = 800 L
so the next time we have a node at the closed and a max at the open end is when
wavelength = (4/3)L
c = (4/3)L*f = 800 L
f = 800 *3/4 = 600 Hz <-------
the next time is when
5/4 wavelength = L
c = (4/5)L*f= 800 L
f = 1000 Hz <--------
200, 600, 1000
1 answer