Practice question

**Mechanical waves** require medium and can be transverse or longitudinal. Sound in air is longitudinal since fluids support only compressional motion, while string waves are transverse. Progressive waves transfer energy without net mass transport, distinguishing from standing waves. In transverse waves on a string, the tension provides the restoring force that opposes displacement, enabling wave propagation, unlike elasticity or pressure in other contexts. Using v = fλ and standing-wave condition fₙ = n v/(2L) or v/(4L) as applicable, calculation yields Tension, illustrating frequency-length-speed interdependence and quantization by boundaries.