Question

Two closed pipes produce 10 beats per second when emitting their fundamental frequency. If their lengths are in ratio of $25:26$ respectively. Then their fundamental frequency in $Hz$, are

• A. 270, 280
• B. 260, 270
• C. 260, 250
• D. 250, 260

Answer 1

The correct option is C 260, 250

Beat frequency is given by
$\begin{array}{}{f}_1-f_2=10& \text{(1)}\end{array}$
Fundamental frequency $f\propto \frac{1}{l}$
$\begin{array}{}\frac{f_1}{f_2}=\frac{l_2}{l_1}=\frac{26}{25}& \text{(2)}\end{array}$
Solving equations 1 and 2 $f_1=260Hz,f_2=250Hz$