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Re: Lenz's Law



You are correct about the counter-clockwise current in the conducting
ring. That current is driven by an induced electric field that forms
closed loops. These closed loops have a counterclockwise sense (in
the region to the right of the wire).

That induced electric field is found not only in the loop, but in all the
space surrounding the wire. Thus, if you sketch it out, you will see that
the induced electric field has a component to the south in the wire, thus
opposing the conventional current INCREASE in the wire.

(To the left of the wire, the closed loops are clockwise, also giving a
southward component of the induced electric field in the wire.)

(If the northward current is decreasing, the induced currents and electric
fields are reversed, giving a northward induced electric field in the wire
to oppose the conventional current DECREASE in the wire.)

This is indeed a mutual inductance situation and shows Lenz's Law: The
direction of the magnetic induction effect is such as to oppose the cause
of the effect.

Tom Sandin