Modes of vibrations of air column in a closed pipe.
- The air at the closed end is not free to vibrate so a node is formed at the closed end.
- While the air at the open end is free to vibrate with maximum amplitude so an antinode is formed at this end.
- This is the simplest mode of vibration and is called fundamental mode.
where,
v is the velocity of sound in air,
L is the length of the vibrating column,
λis the wavelength.
Second mode : or first overtone — [Figure (2)]
Similarly for third mode or second overtone [figure (3)]
