If we study the vibration of a pipe open at both ends, which of the following statements is not true?

Options

A. Open end will be antinode
B. Odd harmonics of the fundamental frequency will be generated
C. All harmonics of the fundamental frequency will be generated
D. ressure change will be maximum at both ends

Answer

To determine which statement is not true regarding the vibration of a pipe open at both ends, we need to analyze the characteristics of such a pipe.

### Step-by-Step Solution:

1. **Understanding Pipe Vibrations**:
- A pipe open at both ends supports standing waves. The ends of the pipe are displacement antinodes (points of maximum displacement) and pressure nodes (points of minimum pressure variation).

2. **Identifying Nodes and Antinodes**:
- In a pipe open at both ends, the pressure variation is minimum (node) at the ends and maximum (antinodes) at the center of the pipe. This means that the pressure changes the least at the ends of the pipe.

3. **Harmonics in Open Pipes**:
- Open pipes can support both odd and even harmonics. The fundamental frequency (first harmonic) and higher harmonics (second, third, etc.) can all be produced in a pipe open at both ends.

4. **Evaluating the Statements**:
- We need to evaluate the given statements about the pipe. The statement that claims "pressure change will be maximum at both ends" is incorrect because, as established, the pressure change is actually minimum at the ends.

5. **Conclusion**:
- Therefore, the statement that is not true is: "Pressure change will be maximum at both ends."

### Final Answer:
The statement that is not true is: "Pressure change will be maximum at both ends."

---