Electromagnetism

By: Hannah Tender and Jadynn Veigel

What is Electromagnetism?

The interaction of electric currents or fields and magnetic fields

Real Word Applications● An Electric Generator → An electrical device that turns electrical energy into

mechanical energy.● Back EMF in Electric Motors → Large items such as refrigerators or air

conditioners use these motors.● Transformers → Electricity runs through power lines

Electrical Forces● An electrical force is a mixture of protons and electrons that attract and repel. ● The forces depend on the motions of the charges.● The force between the moving charges is called a magnetic force.● The magnetic force creates an electrical charge, which is magnetism.

Magnets● The ends of a magnet are called magnetic poles. They behave like electric

charges.● Like Poles → repel (+ & +)● Unlike Poles→ attract (- & +)

Magnets● Magnetic monopoles are poles that isolate a magnet. ● Magnets poles are names after the direction they are pointing (north & south)● Magnets are surrounded by magnetic fields just like electric charges are

surrounded by electric fields. ● Fun Fact→ The only elements that occur naturally in a magnetized state is iron,

nickel, and cobalt.

Electric Currents and Magnetism● Hans Christian Oersted, a Danish scientist, discovered the connection between

electricity and magnetism in 1820 while performing a demonstration:○ A compass needle experiences a force when it is bright near a current-carrying wire

● Motion of the charges must produce the field● The direction of the magnetic field is shown by the right-hand rule

○ Thumb of your right hand points in the direction of the positive current, your fingers point to the

direction of the magnetic field

Making Magnets● A magnet can be made by wrapping wire around iron. ● The current passes through the coil in the wire, creating a magnetic field along

the axis of the coil.● The current and the wire creates an electromagnet.

Electromagnetic Units● Ampere is the SI unit for electrical currents.● Tesla is the SI unit for magnetic fields.● Sometimes the SI unit for magnetic fields will be gauss, instead of tesla.

Charged Particles in Magnetic Fields● An electric current is a stream of charged particles.● If the charge is not moving the magnetic force on a charged particle is zero.

Magnetism and Electric Currents

● British scientist Michael Faraday discovered that motion is the key to producing an electric current with a magnet

● If a wire is moving through a magnetic field, a current is produced● It’s the relative motion of the wire and the magnet that is important because of

the principle of relativity● Reversing the direction of the bar it reverses the direction of the current

http://www.youtube.com/watch?v=Fd3O6sXBXqA

Generator and Motors● Faraday discovered an electric generated. The generator is made with a metal

and a wire. The wire wraps around the metal and the loops from the wire rotates and creates an electrical charge. The charge then gets carried into a circuit.

Electromagnetic Waves● James Clerk Maxwell calculated electromagnetic waves that take the form of

oscillating electric and magnetic fields that travel with a speed to that light.● In 1887 Heinrich Hertz produces electromagnetic waves on one side of a room

and detected them from another.

http://www.youtube.com/watch?v=HeXV3Ic8phw

Key Terms● Magnetic poles: one end of a magnet● Magnetic monopoles: a hypothetical, isolated magnetic pole● Magnetic field: the space surrounding a magnetic object● Electromagnet: A magnet constructed by wrapping wire around an iron core● Ampere: The SI unit of electric current● Tesla: The SI unit of magnetic field● Gauss: A unit of magnetic strength; 10¯⁴ tesla

Works Citedhttps://www.youtube.com/watch?v=HeXV3Ic8phw

http://www.feynmanlectures.caltech.edu/II_01.html

http://physics.bu.edu/~duffy/PY106/Electricgenerators.html