Which of the following does not exhibit polarization

The correct option/answer is Longitudinal wave in a gas.

To understand why a longitudinal wave in a gas cannot exhibit polarization, let us break down the physical concepts of waves and polarization step-by-step:

1. What is Polarization?
   Polarization is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. A wave is polarized if its vibrations are confined to a single plane perpendicular to the direction of propagation of the wave.


2. Transverse Waves vs. Longitudinal Waves:
   - In a transverse wave, the particles of the medium oscillate perpendicular to the direction in which the wave travels. Because there are infinite possible directions perpendicular to the wave propagation direction, we can restrict these vibrations to a single plane (i.e., polarize them).
   - In a longitudinal wave, the particles of the medium oscillate back and forth parallel to the direction of wave propagation.


3. Why Longitudinal Waves Cannot Be Polarized:
   Since the displacement of particles in a longitudinal wave (such as a sound wave in a gas) is strictly along the direction of travel, there is only one direction of oscillation. There are no perpendicular components of vibration to restrict or filter into a specific plane. Consequently, longitudinal waves cannot be polarized.

Therefore, a longitudinal wave in a gas does not exhibit polarization, making "Longitudinal wave in a gas" the correct answer.