Question

The early seismometers adopted the idea that in order to record the earthquake, it is

• A. the pen that should move just as it moves when we write on paper
• B. the pen that should stay still and the paper should move
• C. both pen and paper that should move
• D. neither pen nor paper that should move

Answer 1

Answer:

B. the pen that should stay still and the paper should move

The correct answer is: "the pen that should stay still and the paper should move" This is because the passage explains that the key to recording earthquake waves lies in the observation that when a sudden start is made (like in a bus or train), a person tends to fall because their feet move while their head stays still. Therefore, to effectively record earthquake waves, the pen (representing the head) should stay still while the paper (representing the moving ground) should move.