Question

The instrument used in the laboratory to produce sound of a fixed frequency is:
A. Simple pendulum
B. Metre scale
C. Thermometer
D. Tuning fork

Answer 1

Hint:-Fixed frequency means, attached or placed so as to be immovable not subject to change and stable.We will use the instrument in the laboratory for producing sound which is not movable and thus no change in frequency.From options, we will inspect each instrument and find out which instrument is stationary and produce sound.

Complete step-by-step solution:
Let’s check one by one each option and find out the instrument which is immovable and produces sound.
1. Simple pendulum: a pendulum is a body suspended from a fixed support so that it can swing freely back and forth under the influence of gravity.
We find pendulum is a movable instrument, so it is not the correct option.
2. Metre scale: metre scale is a standard measuring instrument, used for measuring various length and heights. We found that meter scale is a stationary instrument but does not produce sound, so it is also not a correct option.
3. Thermometer: it is an instrument used to measure temperature of the human body and various other objects. Thermometer also does not produce sound but it is a fixed instrument .
4. Tuning fork : A tuning fork is the instrument used to produce sound of a fixed frequency because it is not a moving instrument .
Our search for the instrument of fixed frequency is complete and option 4 is correct

Note:- Phenomenon responsible for producing sound in an instrument is Resonance .Resonance is an increased amplitude situation that occurs when the frequency of a periodically applied force is equal to or close to a natural frequency of the instruments on which it acts.