Question

overtone (harmonics) occur at those that produce standing waves in a string attached at both ends. decibels nodes frequencies distances

Explanation:

• Decibels measure sound intensity, not related to producing standing waves for overtones.
• Nodes are points of zero displacement in a standing wave, not the entity that "produces" overtones.
• For a string fixed at both ends, overtones (harmonics) occur at specific frequencies. The fundamental frequency \(f_1=\frac{v}{2L}\) (where \(v\) is wave speed and \(L\) is string length), and overtones are \(f_n = nf_1\) (\(n = 2,3,\cdots\)).
• Distances do not directly produce overtones; it is the frequency - wavelength relationship (\(v=\lambda f\)) that is key for standing - wave formation (including overtones) in a string.

Answer:

C. frequencies