Transverse vs Longitudinal Waves: Difference, Examples and Diagrams

Sound in air (and in any gas or liquid) is a longitudinal wave. The air molecules move back and forth in the same direction that the sound travels, making regions of compression (pushed together) and rarefaction (spread apart). Gases and liquids cannot support the sideways (shear) motion that a transverse wave needs, so sound through them is always longitudinal. NCERT states this directly, and NEET loves the fact that sound is longitudinal, not transverse.

Yes. Both transverse and longitudinal waves carry energy from one place to another, but the medium as a whole does not travel with the wave. Each particle only oscillates about its own fixed position and passes the disturbance to the next particle. The difference is only the direction of that oscillation relative to the wave's travel, not whether energy moves.

Sound is a mechanical wave, so it needs a material medium (air, water, solid) whose particles can vibrate. In a vacuum there are no particles, so sound cannot pass. Light is an electromagnetic wave (a transverse wave of electric and magnetic fields) and needs no medium, so it crosses empty space. This is a mechanical vs electromagnetic point layered on top of the transverse/longitudinal idea.

No, not in the up-down sense. Crest and trough are the maximum and minimum displacement points of a transverse wave. In a longitudinal wave the equivalent high-pressure and low-pressure regions are called compressions and rarefactions. If you plot a longitudinal wave's displacement, the graph looks like a sine curve, but the real particle motion is back and forth, not up and down.

Water surface waves are a combination of both. Each water particle moves in a small circle, which mixes up-down (transverse) and back-forth (longitudinal) motion. NCERT lists ripples from a motorboat as 'transverse and longitudinal' for this reason. For NEET, remember water waves are not purely transverse.

In a transverse wave the medium particles vibrate perpendicular (at 90 degrees) to the wave's direction of travel. In a longitudinal wave they vibrate parallel to it, along the same line.

Transverse: a wave on a stretched string and light (electromagnetic) waves. Longitudinal: sound waves in air and a compression pulse sent along a slinky spring pushed along its length.

Only transverse waves can be polarised, because their vibration has a definite sideways direction that can be restricted. Longitudinal waves vibrate along the travel direction and cannot be polarised. This is a common NEET/JEE distinguishing point.

Yes. Solids can support shear (sideways) forces, so solids carry both transverse and longitudinal sound waves. In gases and liquids, sound is only longitudinal.

Not necessarily. The same medium can support both, but their speeds are usually different because they depend on different properties (for example, shear modulus vs bulk modulus in a solid).