Question

A standing wave propagating with velocity $300m/s^{-1}$ in an open pipe of length $4m$ has four nodes. The frequency of the wave is

• A. 75 Hz
• B. 100 Hz
• C. 150 Hz
• D. 300 Hz
• E. 600 Hz

Answer 1

Answer: (C)

Nodes are produced in the open pipe as shown in figure.
So,$2\lambda =4$
$\lambda =\frac{4}{2}=2m$
From wave equation,
$V=n\lambda$
$n=\frac{V}{\lambda }$
$=\frac{300}{2}$
$=150Hz$