A glass tube of length `1.5 m` is filled completely with water , the water can be drained out slowly at the bottom of the tube . Find the total number of resonance obtained , when a tuning fork of frequency `606 Hz` is put at the upper open end of the tube , `v_(sound) = 340 m//s`.

Options

A. `2`
B. `3`
C. `4`
D. `5`

Answer

D

Explanation

Wavelength of sound
`= (v)/(f) = (340 m//s)/( 606 s^(-1)) = 56.1 cm`
Since , closed pipe allows only odd harmonics , so
`f = ( 2n + 1) (v)/( 4 l) or ,l = ( 2n + 1) (v)/( 4 f) , n in I`
or , `l = ( 2 n + 1) xx 14 cm`
`:. L = 14 cm , 42 cm , 70 cm , 98 cm , 126 cm , 154 cm , etc`.
Since `l gt 150 cm`
`:.` No. of resonances `= 5`