Who Performs Work in EMF Generation with Changing Magnetic Fields?

AI Thread Summary
EMF generation occurs when a closed loop of wire moves through a magnetic field, with the work being performed by the individual pushing or rotating the coil. It is confirmed that EMF can also be generated through a changing magnetic field without the need for coil rotation, as the changing magnetic flux induces an EMF. Most large generators and alternators utilize this principle, where a magnet is rotated inside fixed coils to produce electricity. The discussion clarifies that both constant and non-constant magnetic fields can effectively generate EMF. Understanding these principles is crucial for applications in electrical engineering and generator design.
fricke
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I understand that EMF is generated by moving a closed loop of wire through a constant magnetic field. I am confused about one thing, who is actually doing work here? (of course it is not magnetic field).
 
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and one more question. Can EMF be generated through non-constant magnetic field? say, the magnetic field is changing with time.
 
Question 1: You are doing the work by pushing or rotating the coil.
Q2: Yes. If the magnetic field is changing with time, you don't have to rotate the coil. The changing magnetic flux induces an emf.
 
fricke said:
and one more question. Can EMF be generated through non-constant magnetic field? say, the magnetic field is changing with time.

yes, that's the way most large generators/alternators work. The magnet is rotated on a shaft inside the surrounding fixed coils

Dave
 

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