ATAR Notes: Forum
HSC Stuff => HSC Science Stuff => HSC Subjects + Help => HSC Physics => Topic started by: BakerDad12 on May 04, 2020, 08:27:35 am
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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?
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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.