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MHT CET · Physics · Waves and Sound

The length and diameter of a metal wire used in sonometer is doubled. The fundamental frequency will change from ' \(n\) ' to

  1. A \(\frac{\mathrm{n}}{4}\)
  2. B n
  3. C 2n
  4. D \(\frac{\mathrm{n}}{2}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{\mathrm{n}}{4}\)

Step-by-step Solution

Detailed explanation

The fundamental frequency is given by
\(\mathrm{n}=\frac{1}{2 \mathrm{Cr}} \sqrt{\frac{\mathrm{T}}{\pi \rho}}\)
\(\begin{aligned} & \therefore \mathrm{n} \propto \frac{1}{\ell_{\mathrm{r}}} \\ & \therefore \frac{\mathrm{n}_2}{\mathrm{n}_1}=\frac{\ell_1 \mathrm{r}_1}{\ell_2 \mathrm{r}_2}=\frac{1}{2} \times \frac{1}{2}=\frac{1}{4}\end{aligned}\)
\(\therefore \mathrm{n}_2=\frac{\mathrm{n}_1}{4}=\frac{\mathrm{n}}{4}\)