Mutual Induction and Law of Conservation of Mass

[Nishantkumar19]

In mutual induction, when a coil is turned on or off, it generates voltage in another nearby coil. But where is that voltage coming from? It can't be created, so what form of energy does it convert from?

As far as I know, when the magnetic field cuts across the coil, that generates voltage, but does the magnetic field itself lose energy that is being converted to voltage in the second coil?

 

[Drakkith]

Yes, the energy comes from the magnetic field, which comes from the first coil.

 

[tech99]

Yes, the energy comes from the magnetic field, which comes from the first coil.

If the second coil is open circuit, no energy flows to it. When the first coil has a varying magnetic field, as with AC, it applies an electro motive force to the electrons in the secondary, but as there is an open circuit they cannot move and so no energy is absorbed.

 

[Drakkith]

If the second coil is open circuit, no energy flows to it. When the first coil has a varying magnetic field, as with AC, it applies an electro motive force to the electrons in the secondary, but as there is an open circuit they cannot move and so no energy is absorbed.

What does this have to do with the OP's question or my response?

 

[tech99]

What does this have to do with the OP's question or my response?

My apologies if I have missed the point, but the questioner seemed to be asking if, to induce a voltage in a nearby coil, energy is taken from the field of the primary, and that was the direction of my reply.

 

[Drakkith]

My apologies if I have missed the point, but the questioner seemed to be asking if, to induce a voltage in a nearby coil, energy is taken from the field of the primary, and that was the direction of my reply.

I see. It seemed like you were chiming in just to point out something about an open circuit. No worries.

 

[Nishantkumar19]

Does that mean the primary field loses energy over time?

Does the same apply for when an electromagnetic field attracts iron objects?

Is it the size of the field that diminishes, or the attracting energy itself?

Thanks for all your help.

 

[Drakkith]

Does that mean the primary field loses energy over time?

If not replenished by the primary circuit, yes. That's why when you turn of the primary, the secondary side shuts off too.

Does the same apply for when an electromagnetic field attracts iron objects?

That is beyond my expertise.