9702 · 7.2
Transverse and longitudinal waves — FAQ
Frequently asked questions for 9702 Transverse and longitudinal waves. Direct answers first, then deeper explanation — then practise with marking.
What's the main difference between transverse and longitudinal waves?
The main difference lies in the direction of particle oscillation relative to the wave's energy transfer. In transverse waves, particles oscillate perpendicular to energy flow, while in longitudinal waves, they oscillate parallel to it.
Why can't sound waves be polarised?
Sound waves are longitudinal waves, meaning their particles oscillate back and forth parallel to the direction of wave propagation. Polarisation requires restricting oscillations to a single plane perpendicular to the direction of travel, which isn't possible for a longitudinal wave.
How do waves transfer energy without transferring matter?
Waves transfer energy through the vibrations or oscillations of particles in a medium, or through oscillating fields in a vacuum (for EM waves). The particles themselves simply move back and forth about a fixed position, passing the energy along, rather than moving with the wave.