NDA2026General AbilityGeneral StudiesActual
Consider the following statements: I. In a seismograph, P waves are recorded earlier than S waves. II. 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?
Options
- AI only
- BII only
- CBoth I and II
- DNeither I nor II
Correct answer
C. Both I and II
Step-by-step solution
P waves are primary waves and travel faster than S waves. Thus, they reach the seismograph first and are recorded earlier. Statement I is correct. P waves are longitudinal waves, meaning the particles of the medium vibrate to and fro parallel to the direction of wave propagation. S waves are transverse waves, meaning the particles vibrate perpendicular to the direction of wave propagation. Statement II is correct. Both statements I and II are correct. Answer: Both I and II