When asked how to create an electromagnet, the best answer would be, "you can create an electromagnet by a. applying a direct current to a non–magnetic material in order to create an electromagnetic field." b.  covering a wire with insulation and applying a direct electrical current to the magnet." c.  coiling a ferromagnetic material, wrapping in an insulator, and applying a current to the coil." d.  wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current."

Choice-D will do the job nicely.

Letter a, because when there are unlike charges they will always attract to each other.

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.