gs1medium
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 waves 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?
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
▶ Answer & Explanation
Correct answer: C. Both 1 and 2
Primary (P) waves are compressional waves and travel fastest through solids, liquids, and gases, thus arriving first at a seismograph. Secondary (S) waves are shear waves and are slower, travelling only through solids. The particle motion in P waves is parallel to the wave's direction of travel, while in S waves, it is perpendicular.
Source: UPSC gs1 2023