Electric field lines form closed loops aroud a time-varying magnetic field.

 I think you are getting confused between fields and currents in a circuit. Fields exist in a spacial medium. A circuit is a network of wires and components. There are fields inside the wire and the components, but the circuit does not constitute a field. If you are referring to static conditions only, then electic fields must start and end on charges. Only when time variations occurs can electric fields form closed loops.

 Even in a closed circuit, there must be a source of potential. All electric fields will begin and end at that potential source (battery, power supply, etc.) This forms a closed circuit, and the electric current loops the circuit, but the "electric field", which we could imagine is the voltage from the source divided by the length of the circuit, starts and stops at the potential source (which contains charges), This is only an an analogy, because there is no real electric field involved.
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Regards,
Ramesh
IIT Kgp - 05 batch




						

							
Hi,
Yes, Electricity Loops are closed circuits.
Regards
Rajat