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?
- A1 only
- B2 only
- CBoth 1 and 2Correct
- DNeither 1 nor 2
Explanation
Let's analyze the statements regarding seismic waves:
-
In a seismograph, P waves are recorded earlier than S waves. This statement is correct. P-waves (Primary waves) are compressional waves that travel through solids, liquids, and gases. They are the fastest seismic waves. S-waves (Secondary waves) are shear waves that can only travel through solids and are slower than P-waves. Consequently, P-waves are always the first to arrive and be recorded by a seismograph after an earthquake.
-
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. This statement is correct. This accurately describes the nature of P-waves as longitudinal waves (particle motion is parallel to wave direction, causing compression and rarefaction) and S-waves as transverse waves (particle motion is perpendicular to wave direction, causing shaking or shearing).
Both statements are correct.

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