We have this stationary loop in a time-varying B-field. The current I (in red) is induced by the changing field B(t). This current in turn induces a B field that opposes the changing field due to right-hand-rule. But, I dont understand is why the first field B(t) does not obey the right-hand-rule since it induces a current in the opposite direction of what I would expect if I put my fingers in the B fields direction and my thumb would point in the opposite of the current that is in the picture. Why does the induced current go that way due to B(t)?

enter image description here


1 Answer 1


If B is increasing, then the indicated induced B and the direction of induced current are correct. The polarity indicated in red is not. The near side of the resistor will be positive. A voltage drop occurs across the resistor.

  • $\begingroup$ Oh so everything is correct in this image escept for the voltage across the resistor which should be -Vemf according to the picture? $\endgroup$
    – Clone
    Commented Jan 9, 2021 at 20:27
  • $\begingroup$ I'm not sure what is represented by the arrow labeled C. $\endgroup$
    – R.W. Bird
    Commented Jan 9, 2021 at 21:06
  • $\begingroup$ You should expand on why the induced B field and current point the way they do so as to help the poster understand. $\endgroup$
    – Triatticus
    Commented Jan 10, 2021 at 1:52

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