An open pipe emits a fundamental frequency $n$ when it emits the 3rd harmonic, then the pipe can accommodate

• A

  2 nodes, 2 anti-nodes
• Correct answer
  B

  3 nodes, 4 anti-nodes
• C

  3 nodes, 3 anti-nodes
• D

  1 node, 2 anti-nodes

Solution

For third harmonic, $n=3$. So, for an open pipe, the propagation of waves can be shown as

$\therefore$ Nodes $=3$ and anti-nodes $=4$

Hence, the correct answer is option: 'B'.