Which of the following are the characteristics of electromagnetic waves? 1) They are elastic waves. 2) They can also move in a vacuum. 3) They have electric and magnetic components which are mutually perpendicular. 4) They move with speed equal to 3 lakh meters per second. Select the correct answer using the code given below:

Electromagnetic (EM) waves are transverse waves consisting of synchronized oscillations of electric and magnetic fields. Unlike mechanical waves, which are elastic waves requiring a medium to propagate through compression and rarefaction, EM waves do not require a medium and can travel through a vacuum [1]. A defining characteristic is that their electric and magnetic field components oscillate at right angles (mutually perpendicular) to each other and to the direction of wave propagation. In a vacuum, all EM waves travel at the speed of light, which is approximately 3!5 10^8 meters per second (300,000,000 m/s). Statement 4 is incorrect because it cites the speed as "3 lakh meters per second" (300,000 m/s), which is three orders of magnitude slower than the actual speed of light. Therefore, only statements 2 and 3 are correct.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 5: Earths Magnetic Field (Geomagnetic Field) > Why Do Sound Waves Travel Faster In A Denser Medium Whereas Light Travels Slower? > p. 64