Who Performs Work in EMF Generation with Changing Magnetic Fields?

[fricke]

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).

 

[fricke]

and one more question. Can EMF be generated through non-constant magnetic field? say, the magnetic field is changing with time.

 

[Chandra Prayaga]

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.

 

[davenn]

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