Question

Two closed pipe produce 10 beats per second when emitting their fundamental nodes. If their length are in ratio of 25 : 26. Then their fundamental frequency in Hz, are

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

Answer 1

Answer: (C)

260, 250

Answer 2

$n_{1} - n_{2} = 10$ ..…(i)

Using $n_{1}, = \frac{v}{4l_{1}}$ and $n_{2} = \frac{v}{4l_{2}}$

⇒ $\frac{n_{1}}{n_{2}} = \frac{l_{2}}{l_{1}} = \frac{26}{25}$ …..(ii)

After solving these equation $n_{1} = 260Hz$,$n_{2} = 250Hz$