A turning fork of frequency 340Hz is vibrated just above a cylindrical tube of height 1.2m. If water is slowly poured into the tube, at what maximum height ...
A turning fork of frequency 340Hz is vibrated just above a cylindrical tube of height 1.2m. If water is slowly poured into the tube, at what maximum height will resonance occur.
[speed of sound in air = 340ms-1]
Answer Details
In vibration in a closed pipe/tube, the first resonance occurs at a position L = V/4f, when reading from the top of the tube,
L1 =
_340
4 x 340
= 0.25m L2 = 3V/4f
L2 =
3 x 340
4 x 340
= 0.75m L3 = 5V/4f
L3 =
5 x 340
4 x 340
= 1.25m However, the effective length of the tube is 1.2m. Thus reading from below, the first position of resonance will be 1.20 - 0.75m = 0.45m