Physic Labs

Problem 1

A string of length LL fixed at both ends carries waves at speed vv. Find the fundamental wavelength and frequency, and the frequency of the nnth harmonic. A uniform string of length LL has nodes at both fixed ends; consider mode number nn, a positive integer. (a) Find wavelength λn\lambda_n and the number of interior nodes. (b) Find the fundamental frequency. (c) Find the frequency of mode nn and explain its harmonic relation. Express each answer in terms of the supplied parameters, using SI units for any numerical evaluation. State the assumptions used, check dimensions at each result, and compare with the governing law to catch a sign error or a missing condition.
fn=nv2L,λn=2Lnf_n=\frac{nv}{2L},\quad \lambda_n=\frac{2L}{n}
problems.proof.analysis

Use the earlier results in that additional relation to obtain the last requested quantity. Checking its sign distinguishes a mathematical magnitude from a physically admissible state.