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?
A
1 only
B
2 only
C
Both 1 and 2
D
Neither 1 nor 2
Correct Answer: Option C
Explanation
1. Statement 1: P waves (Primary waves) travel faster through the Earth's interior than S waves (Secondary waves). Consequently, when an earthquake occurs, P waves arrive at a seismograph station first and are recorded earlier than S waves. This statement is correct.
2. Statement 2: This statement accurately describes the particle motion associated with each wave type. P waves are longitudinal waves, where particles vibrate parallel to the direction of wave propagation (compressions and rarefactions). S waves are transverse waves, where particles vibrate perpendicular (up and down or side-to-side) at right angles to the direction of wave propagation. This statement is correct.
3. Since both statements are correct, the answer is (C) Both 1 and 2.