Question

The successive resonance frequencies in an open organ pipe are $1944Hz$ and $2600Hz$. The length of the pipe if the speed of sound in air is $328m/s$, is:

• A. $0.40m$
• B. $0.04m$
• C. $0.50m$
• D. $0.25m$

Answer 1

The correct option is D $0.25m$

For an open organ pipe, $n\frac{\lambda }{2}=l$.

$\lambda =\frac{2l}{n}$.

Since $v=f\lambda$, $v=\frac{2fl}{n}$

$f=\frac{nv}{2l}$

$1944=\frac{328n}{2l}$ and $2600=\frac{328(n+1)}{2l}$

Subtracting the two equations, we get,

$656=\frac{328}{2l}$

$l=0.25m$