When the open organ pipe resonates in its fundamental mode then at the centre of the pipe

Options

A. The gas molecules undergo vibrations of maximum amplitude
B. The gas molecules are at rest
C. The pressure ofthe gas is constant
D. The pressure ofthe gas undergoes maximum variation

Answer

B, D

Explanation

In fundamental mode of open pipe, at its center there is displacement node so gas molecules are at rest and pressure variation will be maximum