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A stationary wave is formed on a stretched wire - AQA - A-Level Physics - Question 3 - 2019 - Paper 3
Question 3
A stationary wave is formed on a stretched wire. Figure 14 shows the wire, fixed at one end, supported by two bridges and passing over a pulley. A 0.500 kg mass is... show full transcript
Worked Solution & Example Answer:A stationary wave is formed on a stretched wire - AQA - A-Level Physics - Question 3 - 2019 - Paper 3
Step 1
Determine $f$, the frequency of the alternating pd.
Answer
To find the frequency , we can use the time-base settings from Figure 16. The time setting is 10 ms cm, and one full waveform (one complete cycle) spans a distance of 5 cm (5 divisions on the oscilloscope). The time period for this waveform can be calculated as:
The frequency can then be found using the formula:
f = rac{1}{T} = rac{1}{0.050 ext{ s}} = 20 ext{ Hz}
Step 2
Determine the wavelength $ abla$ of the stationary wave shown in Figure 17.
Answer
From Figure 17, we note that the stationary wave exhibits three complete wavelengths between the two bridges, which measures approximately 24 cm. Thus, the wavelength can be calculated as:
abla = rac{24 ext{ cm}}{3} = 8 ext{ cm} = 0.08 ext{ m}$$Step 3
Step 4
Step 5
Step 6
Describe relevant procedures to limit the effect of random error in the result for $d$.
Answer
To limit random error in measuring diameter , the following procedures can be implemented:
- Take multiple measurements at different positions along the rod and calculate an average.
- Ensure the calipers are properly calibrated before use to eliminate systematic errors.
- Measure the diameter in different orientations to ensure uniformity.
Step 7
Determine the density of the rod.
Answer
To find the density, use the formula:
ho = rac{ ext{mass}}{ ext{volume}}$$ Given that mass per unit length is 3.54 × 10$^{3}$ kg m$^{-1}$, and assuming a cross-sectional area $A$ (calculated from part earlier), we can express the density as: $$ ext{density} = rac{3.54 imes 10^{3}}{A}$$