Question

A tube closed at one end containing air produces fundamental note of frequency $512\, Hz$. If the tube is open at both the ends, the fundamental frequency will be

• A. 1024 Hz
• B. 256 Hz
• C. 1280 Hz
• D. 768 Hz.

Answer 1

Answer: (A)

1024 Hz

Answer 2

Given: Frequency of fundamental note when tube is closed $\left(n_{1}\right)=512 \,Hz$.
We know that frequency of fundamental note for closed organ pipe $\left(n_{2}\right)=\frac{v}{2 l}$ and for open pipe $\left(n_{1}\right)=\frac{v}{4 l}$ or $n_{2}=2 n_{1}=2 \times 512$
$=1024 \,Hz$