MOVEMENT of the particles is at right angles to the motion of the energy is CALLED a transverse wave.Light is an EXAMPLE of a transverse wave.Longitudinal wave: The wave in which the movement of the particles is parallel to the motion of the energy is called a longitudinal wave.A sound wave is an example of a longitudinal wave.Transverse waves can be polarized because their vibrations can potentially OCCUR in all directions perpendicular to the direction of travel. It is, therefore, POSSIBLE to confine the vibrations to a single plane.Longitudinal waves cannot be plane polarised because the direction of vibration and direction of propagation is the same.Radio waves, x-rays, and visible light waves come under EM waves category. Hence they can be polarized.Sound waves (acoustic waves) are longitudinal waves hence cannot be polarized.