WBJEE · Physics · Waves and Sound
\(A\) whistle whose air column is open at both ends has a fundamental frequency of \(5100 \mathrm{Hz}\). If the speed of sound in air is \(340 \mathrm{ms}^{-1}\), the length of the whistle, in \(\mathrm{cm}\), is
- A \(5 / 3\)
- B \(10 / 3\)
- C 5
- D \(20 / 3\)
Answer & Solution
Correct Answer
(B) \(10 / 3\)
Step-by-step Solution
Detailed explanation
For an open pipe, the frequency \[ \begin{array}{l} f=\frac{v}{2 l} \Rightarrow 5100=\frac{340}{2 \times 1} \\ l=\frac{340}{5100 \times 2} \Rightarrow l=\frac{2}{30 \times 2}=\frac{1}{30} \mathrm{m} \\ l=\frac{100}{30}=\frac{10}{3} \mathrm{cm} \end{array} \]
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