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. Speed: v = √((B/rho)) . 1500 = √((B/1200)) ⇒ 1500² = (B/1200) . B = 1500² × 1200 = 2.7 × 10⁹ Pa . Using v = fλ and standing-wave condition fₙ = n v/(2L) or v/(4L) as applicable, calculation yields 2.7 × 10⁹ Pa, illustrating frequency-length-speed interdependence and quantization by boundaries.