Multiple choiceQuestion 1 · Recall
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By the end you can say what makes a wave transverse or longitudinal, decide which one a given wave is, and give the paired comparison that examiners ask for.
Hold one end of a slinky and flick it sideways. A kink races to the other end.
Now push the same slinky along its length instead. A squeezed patch races along it.
Both carry energy from your hand to the far end, but the material moves in different directions. That single difference is what the words transverse and longitudinal describe.
Two directions matter:
Compare those two directions and you have classified the wave. There is no third option: they are either at right angles or along the same line.
Transverse wave
A wave in which the oscillations are perpendicular to the direction of energy transfer.
Examples: light and every other electromagnetic wave, waves on a rope or a guitar string, ripples on water (treated as transverse at this level), and S-waves in an earthquake.
Longitudinal wave
A wave in which the oscillations are parallel to the direction of energy transfer.
A longitudinal wave is made of compressions, where the particles are pushed closer together, and rarefactions, where they are spread further apart.
Examples: sound in air, water or steel, ultrasound, and P-waves in an earthquake.
| Feature | Transverse | Longitudinal |
|---|---|---|
| Oscillation compared with travel | perpendicular | parallel |
| What you see | crests and troughs | compressions and rarefactions |
| Examples | light, rope waves, S-waves | sound, ultrasound, P-waves |
| Needs a medium? | not always — light crosses empty space | yes |
Everything else is shared. Both transfer energy from one place to another, without carrying the medium along for good. Both have an amplitude, a wavelength, a frequency and a period, and both obey .
That shared list is worth learning, because "state one similarity" is a standard one-mark question.