Florida Teacher Certification Examinations (FTCE) Subject Area Practice Test

If a vibrating string is shortened while maintaining tension, what noticeable change occurs?

1. Volume decrease

2. Pitch increase

3. Frequency decrease

4. Vibration amplitude increase

The correct answer is: Pitch increase

When a vibrating string is shortened while maintaining tension, the tension in the string remains constant, but the effective length of the string decreases. This change in length has a direct impact on the pitch of the sound produced by the string. Specifically, the fundamental frequency of vibration for a string is inversely proportional to its length. When the length of the string is reduced, its natural frequency of vibration increases. Since pitch is closely related to frequency, a higher frequency will produce a higher pitch sound. Therefore, as the string is shortened, the pitch of the sound produced increases. This relationship is fundamental in both music and physics, illustrating how physical characteristics of an instrument—like the length of a string—affect the sound characteristics we hear. In contrast, options that suggest volume decrease, frequency decrease, or increased vibration amplitude do not align with this core principle, as shortening the string while retaining tension leads specifically to an increase in frequency and consequently pitch.