Displacement and Pressure Nodes/Antinodes – Rankers Physics
Topic: Waves
Subtopic: Standing Wave in String and Organ Pipe

Displacement and Pressure Nodes/Antinodes

Assertion (A): In a stationary-wave system, displacement nodes are pressure antinodes, and displacement antinodes are pressure nodes.
Reason (R): When a closed organ pipe vibrates, the pressure of the gas at the closed end remains constant.
 
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution:

In a stationary wave, displacement nodes correspond to points of maximum pressure variation (pressure antinodes) and displacement antinodes correspond to points of minimum pressure variation (pressure nodes). So, (A) is true.

At the closed end of an organ pipe, there must be a displacement node, which is a pressure antinode, meaning there is maximum pressure variation, not constant pressure. Thus, (R) is false.

Leave a Reply

Your email address will not be published. Required fields are marked *