Q. Consider the following statements :
1. In a seismograph, P waves are recorded earlier than S waves.
2. In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation.
Which of the statements given above is/are correct?
Exp) Option c is the correct answer.
Statement 1 is correct: P waves, or Primary waves, are the first waves to arrive at a seismograph. P waves are the fastest seismic waves and can move through solid, liquid, or gas. They leave behind a trail of compressions and rarefactions on the medium they move through. P waves are also called pressure waves for this reason.
Statement 2 is correct: P waves are longitudinal waves, which means that the particle motion occurs parallel to the direction of wave propagation. These waves are compression waves, where particles oscillate back and forth in the same direction that the wave is traveling. As a result, the individual particles vibrate to and fro in the direction of wave propagation. On the other hand, S waves are transverse waves, where particle motion occurs perpendicular (at right angles) to the direction of wave propagation. These waves cause the particles to move up and down or side to side perpendicular to the direction of the wave. Therefore, in S waves, the particles vibrate up and down at right angles to the direction of wave propagation.
Source: https://ncert.nic.in/ncerts/l/kegy203.pdf
Subject) Geography & Environment
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