What is minimum length of a tube, open at both ends, that resonates with tuning fork of frequency 350 Hz ? [velocity of sound in air = 350 m/s]

(1) 50 cm

(2) 100 cm

(3) 75 cm

(4) 25 cm

(1) Fundamental frequency $n=\frac{v}{2l}$

$⇒350=\frac{350}{2L}$$⇒L=\frac{1}{2}m=50\text{\hspace{0.17em}}cm.$

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