A cylinder resonance tube open at both enda has fundamental frequency `F` in air. Half of the length of the tube is dipped vertically in water. The fundamental frequency to the air culumn now is …………………… .

Explanation

In figure (i)
`(lambda)/(2) = l rArr lambda = 2l`
and `f = ( c )/(lambda) = ( c )/(2l)`
In figure (ii)
rArr `(lambda')/(4) = (l)/(2) rArr' = 2l`
and `f' = ( c )/(lambda') = (c )/(2l) = f`
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