NEET Physics: Physics - Sound Waves questions with solutions

Q1. Regarding open organ pipe, which of following is correct?

1. Both ends are pressure antinodes
2. Both ends are displacement nodes
3. Both ends are pressure nodes
4. Both (1)and (2)

Answer: Both ends are displacement nodes

In an open organ pipe, the air at each open end is free to oscillate, so displacement is maximum there, meaning each end is a displacement antinode, not a node. Since pressure variation is opposite to displacement, the open ends are pressure nodes.