If a current carrying wire is wrapped into a loop, the result is a strong magnetic field in the center of the loop. There is an additive effect the fields produced by the wrapped wire. Using the right-hand rule, you can determine the direction of the magnetic field. Click on the image to study the right-hand image showing the direction.
If you loop the wire again, you only increase the magnitude of the magnetic field. Wrapping more and more loops increases the strength of the magnetic field. The strength is directly proportional to the number of loops. If a long wire is looped multiple times, the result is called a solenoid. They have very strong magnetic fields because of the summative effect of the field in the middle. The closer together the field lines are on a field diagram indicate the strength of the magnetic field.
Notice how the magnetic field inside the solenoid resembles the magnetic field of a bar magnet.
Question
What are two ways to increase the magnetic field of a solenoid?
To increase the magnetic field, you can either increase the number of coils or increase the current moving through the wire.
