IAS 2023 — Physics

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?

Consider the following pairs: Objects in space | Description 1. Cepheids | Giant clouds of dust and gas in space 2. Nebulae | Stars which brighten and dim periodically 3. Pulsars | Neutron stars that are formed when massive stars run out of fuel and collapse How many of the above pairs are correctly matched?