Question

A glass tube of `1.0 m` length is filled with water. The water can be drained out slowly at the bottom of the tube. If a vibrating tuning fork of frequency `500 c//s` is brought at the upper end of the tube and the velocity of sound is `300 m//s`, then the total number of resonances obtained will be
A. `4`
B. `3`
C. `2`
D. `1`

Answer 1

Correct Answer - B
`lambda = (v)/(f) = (300)/(500) = 0.6 m`
Resonance will occur at lengths
`(lambda)/(4) , (3 lambda)/(4) , (5 lambda)/(4) , (7 lambda)/(4)` ,…
`0.15 m, 0.45 m, 0.75 m, 1.05 m`, …
`1.05 m` is not possible
Total number of resonances `= 3`