5.84. Electromagnetism http://www.ck12.org
5.84 Electromagnetism
- Define electromagnetism.
- State the right hand rule.
- Explain why electromagnetism is very useful.
Someone’s at the door! She lets the person inside the home know she’s at the door by ringing the doorbell. Does
your home have a doorbell? Did you ever wonder how a doorbell works? The answer is electromagnetism.
What Is Electromagnetism?
Electromagnetismis magnetism produced by an electric current. When electric current flows through a wire, it
creates a magnetic field that surrounds the wire in circles. You can see this in the diagram below. Note that electric
current is conventionally shown moving from positive to negative electric potential, as in this diagram. However,
electrons in current actually flow in the opposite direction, from negative to positive potential.
Q:If more current flows through a wire, how might this affect the magnetic field surrounding the wire?
A:With more current, the magnetic field is stronger.
Right Hand Rule
The direction of the magnetic field created when current flows through a wire depends on the direction of the current.
A simple rule, called the right hand rule, makes it easy to find the direction of the magnetic field if the direction of