Question

A spring fastened firmly between two walls 24cm apart, find the wavelength of the second overtone.

Answer 1

The possible wavelengths of the standing waves in a fixed string are given as follows (see https://brilliant.org/wiki/applying-boundary-conditions-to-standing-waves/):

$$\lambda_n = \dfrac{2L}{n}$$

where $L = 24cm = 0.24m$ is the length of the string, and $n = 1, 2, 3...$ are integer numbers. For the second overtone have:

$$\lambda_2 = \dfrac{2\cdot 0.24m}{2} = 0.24m$$

Answer. 0.24m.