Consider the situation shown in figure. The wire which has a mass of 4.00 g oscillates in its second harmonic and sets the air column in the tube into vibrations in its fundamental mode. Assuming that the speed of sound in air is `40 m s^-1`, find the tension in the wire.
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Explanation

Frequency of wire `f_(2) = (2)/(2 l) sqrt((T)/(mu))`
`= (l)/(l) sqrt((T)/(M//l)) = (1)/(0.4) sqrt((T)/(4 xx 10^(-3)// 0.4)) = 2.5 sqrt(100 T)`
`= 25 sqrt(T)`
Fundamental frequency of closed pipe
`f_(1) = (v)/(4L) = (340)/(4 xx 1) = 85`
`f_(2) = f_(1)`
`25sqrt(T) = 85`
`T = ((17)/(5))^(2) = (3.4)^(2) = 11.56 N`