http://www.ck12.org Chapter 5. Energy
the current is known. The rule is illustrated in theFigure5.182. When the thumb of the right hand is pointing in the
same direction as the current, the fingers of the right hand curl around the wire in the direction of the magnetic field.
You can see the right hand rule in action at this URL: http://www.youtube.com/watch?v=eK1Ar5WPJj8.
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/82395FIGURE 5.182
Uses of Electromagnetism
Electromagnetism is used not only in a doorbells but in many other electric devices as well, such as electric
motors and loudspeakers. It is also used to store information on computer disks. An important medical use of
electromagnetism is magnetic resonance imaging (MRI). This is a technique for making images of the inside of the
body in order to diagnose diseases or injuries. Magnetism created with electric current is so useful because it can be
turned on or off simply by turning the current on or off. The strength of the magnetic field is also easy to control by
changing the amount of current. You can’t do either of these things with a regular magnet.
Summary
- Electromagnetism is magnetism produced by an electric current. Current flowing through a wire creates a
magnetic field that surrounds the wire in concentric circles. - When the thumb of the right hand is pointing in the same direction as the current flowing through a wire, the
fingers of the right hand curl around the wire in the direction of the magnetic field. - Electromagnetism is very useful because it can be turned on or off by turning the current on or off, and it can
be made stronger or weaker by using more or less current.