Physics · Wave Motion and Sound

Only transverse waves can be polarised. Longitudinal waves cannot be polarised.

• Transverse: vibrations perpendicular to the direction of travel of the wave.
• Longitudinal: vibrations parallel to the direction of travel of the wave.

Sound waves are longitudinal so they cannot be polarised.

• Polarised: the wave vibrations occur in one plane only
• Unpolarised: the wave vibrations occur in all planes perpendicular to the direction of travel.

The reason that only transverse waves can be polarised is that 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. Or put another way an unpolarised transverse wave is a 3D shape, it is therefore possible to confine it to a 2D shape (a plane). The vibrations of a longitudinal wave occur along a single line, it is therefore not possible to confine that to a plane, i.e. a 1D shape cannot be confined within a 2D shape. Similarly, Stationary waves and superimposed waves can not be polarised as they are along a single line.

VIDEO EXPLANATION https://www.doubtnut.com/question-answer-physics/if-a-wave-can-be-polarised-it-must-be-11969279

Longitudinal waves cannot be polarized as their oscillations occur parallel to the direction of wave propagation, limiting their ability to confine to a single plane.

Stationary waves result from the superposition of two waves moving in opposite directions and do not exhibit polarization, as they are essentially standing patterns.

Superimposed waves are formed by the combination of multiple waves. While they can exhibit complex behaviors, polarization is not inherently a characteristic of these waves.

Transverse waves can be polarized as their oscillations occur perpendicular to the direction of wave propagation, allowing them to be confined to a single plane.