Discover the magnetic field created by electric current, how electromagnets work, and the force on a current-carrying conductor in a magnetic field.
Any current-carrying conductor creates a magnetic field around it. The right-hand thumb rule gives the direction: point your thumb in the direction of current flow, and your curled fingers show the field's direction.
What rule tells you the direction of the magnetic field around a straight current-carrying wire?
The right-hand thumb rule
A solenoid (coil of wire) carrying current behaves like a bar magnet. Wrapping the coil around an iron core makes a much stronger electromagnet.
Name two ways to increase the strength of an electromagnet.
Increase the number of turns in the coil, or increase the current flowing through it (an iron core also helps)
A current-carrying conductor placed in a magnetic field experiences a force. Fleming's left-hand rule predicts the direction of this force — this is the basic principle behind electric motors.
Which rule predicts the direction of force on a current-carrying conductor in a magnetic field?
Fleming's left-hand rule
1. Does a stationary (non-moving) charge create a magnetic field?
2. What happens to an electromagnet's strength if you increase the number of coil turns?
3. Can an electromagnet be turned off? Can a permanent magnet?
4. Which rule is used for the direction of force in a motor, and which for the direction of field around a wire?
5. What basic device is built directly on the motor effect?