Using Electricity and Magnetism 1/2/2019 1:26 AM Using Electricity and Magnetism Chapter 21 © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

21.1 What Is Electromagnetism? An electric current produces a magnetic field.

21.1 What Is Electromagnetism? The magnetic field produced by a current has three characteristics. The field can be turned on or off, have its direction reversed, or have its strength changed.

21.1 What Is Electromagnetism? An electromagnet is a strong magnet that can be turned on and off.

electromagnetism The relationship between electricity and magnetism.

solenoid A coil of wire with a current that acts as a bar magnet.

electromagnet A magnet created by wrapping a coil of wire with a current around a ferromagnetic core.

21.2 Electricity, Magnetism, and Motion When a wire with a current is placed in a magnetic field, electrical energy is transformed into mechanical energy.

21.2 Electricity, Magnetism, and Motion Electric current is used to turn the pointer of a galvanometer

electric motor A device that transforms electrical energy to mechanical energy

energy The ability to do work or cause change.

electrical energy The energy of moving electrical charges.

mechanical energy Kinetic or potential energy associated with the motion or position of an object.

galvanometer A device that uses an electromagnet to detect small amounts of current.

21.3 Electricity From Magnetism An electric current is induced in a conductor when the conductor moves through a magnetic field.

21.3 Electricity From Magnetism A generator uses motion in a magnetic field to produce an electric current.

electromagnetic induction The process of generating an electric current from the motion of a conductor through a magnetic field.

direct current Current consisting of charges that flow only in one direction in a circuit.

alternating current Current consisting of charges that move back and forth in a circuit.

electric generator A device that converts mechanical energy into electrical energy.

transformer A device that increases or decreases voltage.

step-up transformer A transformer that increases voltage.

step-down transformer A transformer that decreases voltage.