Practice question

**Nature of wave** determines energy transfer mechanism. Longitudinal nature of sound explains propagation through fluids with density variations carrying energy, unlike transverse waves needing rigidity for restoring force. Longitudinal waves require a medium with bulk modulus (resistance to compression), which fluids possess. Transverse waves need shear modulus (resistance to shearing), which fluids lack due to their inability to sustain shear stress. Using v = fλ and standing-wave condition fₙ = n v/(2L) or v/(4L) as applicable, calculation yields Lack of shear modulus, illustrating frequency-length-speed interdependence and quantization by boundaries.