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A tuning fork of frequency `340 Hz` is excited and held above a cylindrical tube of length `120 cm`. It is slowly filled with water. The minimum height of water column required for resonance to be first heard( Velocity of sound `=340 ms^-1`) is.A. 5 cmB. 25 cmC. 45 cmD. 120 cm |
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Answer» Correct Answer - A As the tuning fork is in resonance with air column in the pipe closed at one end `f = (nv)/(4l)` with `n =1 , 3 , 5` So length of air column in the pipe `h = (nv)/(4f) 25 n cm` i.e. `L = 25 cm , 75 cm , 125 cm` So `L = h = 130 cm` `h = 130 - L` `h_(min)=130-L_(max) = 130-125 =5cm` |
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