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 ri

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Q: 75 (IAS/2023)
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?

question_subject: 

Science

question_exam: 

IAS

stats: 

0,15,7,4,2,15,1

Option 1 is correct. In a seismograph, P waves (Primary waves) are indeed recorded earlier than S waves (Secondary waves). This is due to the fact that P waves travel faster through the earth`s crust than S waves.

Option 2 is also correct. P waves cause particles to vibrate in the direction of the wave. This means that as the wave moves forward, the particles also move forward and backward along the same line. However, in the case of S waves, the particle movement is perpendicular to the direction of wave propagation i.e., they move up and down when the wave moves forward. This is why S waves are also known as shear waves or transverse waves.

Therefore, the correct answer is option 3, Both 1 and 2 are correct.