Practice question

**Wave classification** depends on particle vibration relative to propagation. Longitudinal waves have particle oscillation parallel to propagation, creating compressions and rarefactions as in sound in air; transverse have perpendicular oscillation. Tuning fork generates longitudinal sound because air cannot sustain shear. Mechanical waves, such as sound (longitudinal) waves, require a medium for propagation because they rely on particle vibrations. Electromagnetic waves, like light, can travel through a vacuum. Using v = fλ and standing-wave condition fₙ = n v/(2L) or v/(4L) as applicable, calculation yields Sound wave, illustrating frequency-length-speed interdependence and quantization by boundaries.