Question

An object vibrating with a frequency 850 Hz causes resonance in a tube of air when the shortest length of air column is 10.3 cm. Calculate the second resonant length, assuming the speed of sound in air is 340 m/s.

Answer 1

For an opened cylinder the second resonant length will be

$$L=\frac{v}{2f}=\frac{340}{2(850)}=0.2\text{ m}.$$