일반물리학 1 — Waves-I: Problem 20

20 A string under tension \(\tau_i\) oscillates in the third harmonic at frequency \(f_3\), and the waves on the string have wavelength \(\lambda_3\). If the tension is increased to \(\tau_f = 8\tau_i\) and the string is again made to oscillate in the third harmonic, what then are (a) the frequency of oscillation in terms of \(f_3\) and (b) the wavelength of the waves in terms of \(\lambda_3\)?