Which of the following statements is not true of vibrations? Question 9 options: A) Resonance occurs as a result of sympathetic vibrations. B) Two bodies with the same vibration frequency that are placed next to each other will exhibit sympathetic vibrations as one body causes the other to vibrate. C) A non-vibrating object can begin to vibrate as a result of forced vibrations. D) Forced vibrations, such as those between a tuning fork and a large cabinet surface, result in a much lower sound than was produced by the original vibrating body.
The Correct Answer and Explanation is:
Correct Answer: D) Forced vibrations, such as those between a tuning fork and a large cabinet surface, result in a much lower sound than was produced by the original vibrating body.
Explanation:
This statement is not true, which makes it the correct answer to the question.
Forced vibrations occur when a vibrating object causes another object to vibrate. For example, when a tuning fork is placed on a wooden table or cabinet, the surface also starts to vibrate. These vibrations are not random—they match the frequency of the original vibrating object. Instead of lowering the sound, forced vibrations usually amplify the sound.
The large surface area of the table or cabinet helps to push more air molecules, which increases the volume or loudness of the sound. This is why musical instruments often include hollow bodies or soundboards—to enhance and project the sound created by the vibrating strings or air columns.
Let’s evaluate the other options:
- Option A: Resonance does happen due to sympathetic vibrations. When an object naturally vibrates at the same frequency as another vibrating source, it begins to vibrate as well, resulting in resonance and often a stronger sound. This is true.
- Option B: This describes sympathetic vibration correctly. Two objects that share the same natural frequency can cause each other to vibrate if placed close together. This is true.
- Option C: This is a correct definition of forced vibrations. An object that is not vibrating on its own can begin to vibrate due to contact or influence from another vibrating source. This is true.
In conclusion, Option D is incorrect because forced vibrations generally make a sound louder, not lower.
