Answer 1

Given:
Speed of sound in air v = 340 ms⁻¹
We are considering a minimum fundamental frequency of f = 20 Hz,
since, for maximum wavelength, the frequency is a minimum.
Length of organ pipe l = ?
We have :

\[\frac{\lambda}{2} = I\] 

\[ \Rightarrow   \lambda = 2I\]

We know that :
v = fλ

\[\Rightarrow     \lambda = \frac{v}{f}\] 

\[ \Rightarrow l = \frac{v}{2 \times f}\]

On substituting the respective values in the above equation, we get :

\[  I = \frac{340}{2 \times 20}\] 

\[ \Rightarrow   l = \frac{34}{4} = 8 . 5 \text {  m }\]

Length of the organ pipe is 8.5 m.