2 (a) Earthquakes produce seismic waves and infrasound waves - Edexcel - GCSE Physics - Question 2 - 2012 - Paper 1
Question 2
2 (a) Earthquakes produce seismic waves and infrasound waves.
Which row of the table is correct for these waves?
Put a cross (X) in a box to show your answer.
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Worked Solution & Example Answer:2 (a) Earthquakes produce seismic waves and infrasound waves - Edexcel - GCSE Physics - Question 2 - 2012 - Paper 1
Step 1
State what happens to a P-wave when it crosses from the mantle into the core.
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Answer
When a P-wave crosses from the mantle into the core, it slows down and changes direction due to the differing densities and states of the materials.
Step 2
Describe how the speed of a P-wave changes between a depth of 1000 km and 2500 km.
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Answer
Between the depths of 1000 km and 2500 km, the speed of the P-wave increases significantly as it encounters denser layers of the Earth's mantle.
Step 3
Calculate the total time of travel for the wave.
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Answer
To calculate the time, we use the formula:
ext{time} = rac{ ext{distance}}{ ext{speed}}
The total distance is 5800 km and the speed is 12 km/s:
Thus, the total time of travel for the wave is approximately 483.33 seconds.
Step 4
Explain what the results show about predicting earthquakes.
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Answer
The results indicate that it is difficult to predict earthquakes because there is no consistent pattern in the forces required to move the block, similar to the unpredictability of tectonic plate movements. The wide range of forces suggests variability in conditions that makes precise predictions challenging.
