Final answer:
Looping a wire with a current creates a magnetic field, following Ampere's law. The wire's shape affects the magnetic field, while oscillating currents produce electromagnetic waves through accelerating charges.
Step-by-step explanation:
The question is addressing the effects of looping a wire in which a current is flowing. When a wire is looped, it creates a magnetic field around it. This is a consequence of Ampere's law, which is one of the major laws of electricity and magnetism. This law states that a current-carrying wire produces a magnetic field that forms continuous loops around the wire. The shape of the current path influences the shape and strength of this magnetic field. For example, if identical currents are carried in two circular loops where one loop has twice the diameter of the other, the loop with the larger diameter will produce a weaker magnetic field at its center because the magnetic field strength decreases with distance from the current loop.
The concept of an 'infinite wire' is a theoretical construct used to simplify calculations. In reality, no wire is infinite, but in some calculations, we assume an infinitely long straight wire to approximate the behavior of very long wires where the effects of the ends of the wire can be ignored.
Furthermore, electromagnetic waves are produced when the electric currents in the wire oscillate, meaning that their magnitude changes over time. Charged particles that are accelerated produce electromagnetic waves, including light. Consequently, a steady current, which does not change in magnitude or direction, will not produce electromagnetic waves. However, if the current varies or is switched on or off, this can emit electromagnetic waves due to the changing magnetic field.