Which of the following phenomenon is not shown by sound waves ?

Options

A. diffraction
B. interference
C. polarisation
D. none of these

Answer

To determine which phenomenon is not shown by sound waves, we will analyze each of the options provided:

1. **Diffraction**: Sound waves can bend around obstacles and spread out after passing through narrow openings. This bending and spreading is known as diffraction. Therefore, sound waves do exhibit diffraction.

2. **Interference**: When two sound waves meet, they can interfere with each other, leading to constructive or destructive interference. This means that sound waves can indeed show interference.

3. **Polarization**: Polarization is a phenomenon that occurs with transverse waves, where the oscillations are perpendicular to the direction of wave propagation. Sound waves, however, are longitudinal waves, where the oscillations occur in the same direction as the wave propagation. Therefore, sound waves do not exhibit polarization.

4. **None of these**: This option suggests that all the phenomena listed are shown by sound waves. Since we have established that sound waves do not show polarization, this option is incorrect.

Based on this analysis, the answer to the question is:

**Polarization is the phenomenon that is not shown by sound waves.**

### Step-by-Step Solution:
1. Identify the phenomena listed in the options: diffraction, interference, polarization, and none of these.
2. Analyze each phenomenon in relation to sound waves:
- **Diffraction**: Yes, sound waves can diffract.
- **Interference**: Yes, sound waves can interfere.
- **Polarization**: No, sound waves cannot be polarized.
- **None of these**: Incorrect, as polarization is not exhibited by sound waves.
3. Conclude that the phenomenon not shown by sound waves is **polarization**.