Chapter 7, Problem 46R

To determine

To compare: electromagnetic induction and the formation of electromagnets.

Explanation of Solution

Introduction: An electromagnet is a temporary magnet created when a current carrying wire is wrapped around an iron core.

The process of generation of an electric current by a changing magnetic field is known as electromagneticinduction.A magnet moving relative to a wire loop induces current in the wire due to changing magnetic field.

Whereas, an electromagnet is made by wrapping a coil of insulated wire around an iron bar and connecting the wire to a battery. When current flows in the wire, magnetic field is produced and the setup behave as a magnet.

In the process of electromagnetic induction, the magnet does not make a contact with the wire to induce current. Contrary to that, in an electromagnet the iron core has to make contact with the current- carrying wire loop for generation of magnetic field.

Electromagnetic induction uses changing magnetic field to generate current, whereas, an electromagnet produces magnetic field due to flow of current in the wire.

Conclusion:Electromagnetic induction requires a changing magnetic field and no physical contact between the wire and magnet to produce current, whereas, an electromagnet require a physical contact between the iron core and current-carrying wire to produce magnetic field.