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A student carried out a laboratory experiment to find the speed of sound in air - Leaving Cert Physics - Question 3 - 2016
Question 3
A student carried out a laboratory experiment to find the speed of sound in air. (i) Draw a labelled diagram of the arrangement of the apparatus used in this experi... show full transcript
Worked Solution & Example Answer:A student carried out a laboratory experiment to find the speed of sound in air - Leaving Cert Physics - Question 3 - 2016
Step 1
Draw a labelled diagram of the arrangement of the apparatus used in this experiment.
Answer
To draw the arrangement of apparatus used to measure the speed of sound, you should include:
- Resonance Tube: A tube open at one end and closed at the other.
- Tuning Fork: Placed at the open end to produce sound waves.
- Ruler: To measure the length of the tube from the water level to the open end.
- Changing Length Mechanism: Possible use of a sliding mechanism to adjust the water level and thus the length of the air column.
The diagram should label each part clearly, including the direction of sound waves and any other relevant components.
Step 2
How did the student find the frequency of the sound wave used?
Answer
The student would find the frequency of the sound wave by using the formula:
Where:
- f is the frequency,
- v is the speed of sound in air,
- \lambda (lambda) is the wavelength of the sound wave.
In this case, the student may measure the wavelength directly from the resonance tube setup or use tuning forks with known frequencies, ensuring to record the exact frequency of the tuning fork used.
Step 3
What other measurements did the student take?
Answer
In addition to measuring the frequency, the student likely took the following measurements:
- Length of the Air Column: Measured using a ruler from the water surface to the tuning fork.
- Resonance Length: Determined by finding the lengths at which resonance occurs (next harmonics).
- Temperature: To account for environmental conditions that might affect sound speed.
These measurements are crucial for a precise calculation of sound speed.
Step 4
How did the student calculate the speed of sound in air?
Answer
The speed of sound can be calculated using the formula:
Where:
- v is the speed of sound,
- f is the frequency of the sound wave,
- \lambda is the wavelength, which can be derived from the measured length of the air column.
The student would substitute these values into the equation after ensuring they have accurate measurements from their experiment.
Step 5
State one precaution which the student might have taken to get an accurate result.
Answer
One important precaution that the student might take is to ensure that the diameter of the resonance tube is as small as possible so as to minimize the effect of edge diffraction on the sound waves. Additionally, ensuring minimal disturbances in the environment (like background noise) can contribute to obtaining more accurate results.