The diagrams show the displacement–distance graph for a wave and the displacement–time graph for a point in the wave - AQA - A-Level Physics - Question 17 - 2021 - Paper 1
Question 17
The diagrams show the displacement–distance graph for a wave and the displacement–time graph for a point in the wave.
Which is correct for this wave?
A. The amplit... show full transcript
Worked Solution & Example Answer:The diagrams show the displacement–distance graph for a wave and the displacement–time graph for a point in the wave - AQA - A-Level Physics - Question 17 - 2021 - Paper 1
Step 1
A. The amplitude is 3.0 m.
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Answer
The amplitude is the maximum displacement from the rest position. From the displacement-distance graph, the peak displacement reaches 2 m, so this statement is incorrect.
Step 2
B. The wavelength is 6 m.
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Answer
The wavelength is the distance over which the wave's shape repeats, seen in the displacement-distance graph. The distance between two consecutive peaks is 60 m, thus making the wavelength 60 m, not 6 m. This statement is incorrect.
Step 3
C. The speed is 8.3 m s⁻¹.
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Answer
The speed of a wave can be calculated using the formula:
v=fimesλ
From the graph, we have a wavelength of 60 m and a frequency of 0.17 Hz:
v=0.17extHz×60extm=10.2extm/s.
Thus, this statement is also incorrect.
Step 4
D. The frequency is 0.17 Hz.
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Answer
From the displacement-time graph, we can calculate the frequency, which is the number of cycles per second. The graph demonstrates one cycle takes approximately 6 seconds. Therefore, the frequency is
f=6exts1extcycle=0.17extHz.
This statement is correct.