Q122 / 160 · AP EAMCET 2012 · Physics
When a vibrating tuning fork is placed on a sound box of a sonometer, 8 beats per second are heard when the length of the sonometer wire is kept at $101 \mathrm{~cm}$ or $100 \mathrm{~cm}$. Then the frequency of the tuning fork is (Consider that the tension in the wire is kept constant)
- A$1616 \mathrm{~Hz}$
- Correct answerB$1608 \mathrm{~Hz}$
- C$1632 \mathrm{~Hz}$
- D$1600 \mathrm{~Hz}$
Solution
We have, $n l=$ constant
$\begin{aligned} n_1 l_1 & =n_2 l_2 \\ (n+8) 100 & =(n-8) 101 \\ \frac{n+8}{n-8} & =\frac{101}{100} \\ \frac{n}{8} & =\frac{201}{1} \\ n & =1608\end{aligned}$
Hence, the correct answer is option: 'B'.