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MHT CET · Physics · Waves and Sound

The fundamental frequency of open pipe is 'n'. If it is closed from one end then frequency of the \(2^{\text {nd }}\) harmonic of closed pipe is higher by \(200 \mathrm{~Hz}\) than \({ }^{\prime} \mathrm{n}^{\prime}\). The value of 'n' is

  1. A \(800 \mathrm{~Hz}\)
  2. B \(200 \mathrm{~Hz}\)
  3. C \(100 \mathrm{~Hz}\)
  4. D \(400 \mathrm{~Hz}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(400 \mathrm{~Hz}\)

Step-by-step Solution

Detailed explanation

\(\mathrm{n}=\frac{\mathrm{v}}{2 \ell}\)
\(2^{\mathrm{nd}}\) harmonic \(=1^{\mathrm{st}}\) overtone \(=(2 \mathrm{p}+1) \mathrm{n}_{0}=3 \mathrm{n}_{0}\)
\(\frac{3 \mathrm{v}}{4 \ell}-\frac{\mathrm{v}}{2 \ell}=200\)
\(\frac{v}{2 \ell}\left(\frac{3}{2}-1\right)=200\)
\(\frac{v}{2 \ell}=400\)