Question: A vibrating tuning fork of frequency n is placed near the open end of a long cylindrical tube. The t...

Question

A vibrating tuning fork of frequency n is placed near the open end of a long cylindrical tube. The tube has a side opening

and is also fitted with a movable reflecting piston. As the piston is moved through 8.75 cm, the intensity of sound changes from a maximum to minimum. If the speed of sound is 350 metre per second, then n is -

Answer 1

Solution

v = 350 m/sec

Dx = 2x = 2(8.75) = $\frac { \lambda } { 2 }$

l = 4 × 8.75 = 35.00 cm = 0.35 m

v = nl \ n = $\frac { 350 } { 0.35 }$ = 1000 Hz