Practice question

Given: A pipe open at both ends has a third harmonic frequency of 600 Hz and a wave speed of 400 m/s. What is its length? These values define the system as per NCERT data. Formula: v_n = n v/2L, n = 3. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: 600 = 3 × 400/2L Rightarrow 600 = 1200/2L Rightarrow 2L = 2 Rightarrow L = 1 m . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.