Electromagnetic Waves

[BakerDad12]

Hey, I'm confused about EM waves. So it's said that a changing electric field causes a magnetic field which in turn causes an electric field and so on. So aren't we getting an infinite supply of fields and energy? Also, is the fact that a changing electric field  causes a magnetic field something we were meant to know from previous study or not?

[Einstein_Reborn_97]

The answer is yes., the self-propagation of electric and magnetic fields oscillating perpendicular to each other continues infinitely.
The concept of a changing magnetic field producing an electric field is introduced in electromagnetic induction (Faraday's Law). The concept of a changing electric field producing a magnetic field is based on Ampere's Circuital Law.