This might be an absurd question for some of you guys. According to Lenz's Law an induced current will create a magnetic field that induces another current in which it opposes the current causing it at the first place. My question is 'WHY' should it oppose?

I've seen answers on the Internet saying it's the matter of Conservation of Energy, I totally agree on that statement but it doesn't really 'click' my mind, as the statement is something I will always remember, not truly understand. So is there any other possible way to conceptualize/explain that?

  • $\begingroup$ I'm guessing an explanation that is just "because it is experimentally validated" isn't sufficient for you? $\endgroup$ – Aaron Stevens Dec 31 '18 at 5:19
  • $\begingroup$ Do you want more explanation of the conservation of energy argument, or are you looking for a totally different argument for why the EMF is what it is? $\endgroup$ – The Photon Dec 31 '18 at 5:25
  • $\begingroup$ You can think of a varying magnetic field inducing an electric field that in turn stablishes a current. This, together with Maxwell's equations may help you. Note that to stablish the current the circuit must be closed. If you want to recall energy conservation do not forget the Poynting vector. $\endgroup$ – nodarkside Dec 31 '18 at 5:27
  • $\begingroup$ @Aaron Stevens, yes, that was what I meant. $\endgroup$ – acmilan Dec 31 '18 at 14:33

Let us just consider the classic experimental example of Lenz's law: a solenoid, and a bar magnet.

If we move the bar magnet, it induces an emf in the solenoid, current flows, and a magnetic field is induced. This is due to Faraday's Law of electromagnetic induction.

Consider the scenario that Lenz's law doesn't hold, and the magnet experiences an attractive force, into the solenoid. Which in turn leads to acceleration of the magnet, increasing $N\phi$ (magnetic flux linkage). This leads to increased emf and current, which evidently violates the principle of conservation of energy.

  • $\begingroup$ So the explanantion is basically the conservation of energy? I mean I know it opposes because there's no way of creating/producing extra energy out of nothing, the thought I was facing was how and why it really opposes? But if this the only reason on this case, I'll just need to accept that. $\endgroup$ – acmilan Dec 31 '18 at 14:36
  • $\begingroup$ @acmilan yes. that is the reason why the "-" sign is added. $\endgroup$ – QuIcKmAtHs Jan 1 at 4:08

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