Electromagnetic Induction Introducing Faradays Law Earths Magnetic Field

Electromagnetic Induction Introducing Faraday’s Law

Earth’s Magnetic Field • In the outer core, there is a lot of molten Iron, which is believed to create the Earth’s magnetic field • The source of Earth’s magnetic field isn’t stable. Over time it can switch the poles of the Earth. • The period isn’t exact, but we are learning how to predict when the field will switch poles.

Electromagnetic Induction • Just like electric current can produce a magnetic field, magnetism can also produce an electric current inside of a wire. • The motion of a magnet through loops in a wire can create a current inside of the wires.

Electromagnetic Induction • The motion of the magnet creates a voltage, which depends on the relative motion of the conductor (wire) with respect to the magnetic field. • The greater the number of loops, the greater the induced voltage, the greater the current.

Electromagnetic Induction • This is not free energy. You have to put work into the magnet in order to get a voltage. • Also, the more loops you put into the coil, the harder it is to move the magnet through, because the coil acts like a powerful electromagnet and will repel your magnet.

Electromagnetic Induction • The magnet doesn’t have to be the one moving, the motion of the coil relative to the magnet has to be different for this phenomenon to work. • The act of inducing voltage by changing the magnetic field around a conductor is called electromagnetic induction.

Michael Faraday (DO NOT WRITE) • Michael Faraday (1791 -1867) – an English Physicist, who discovered electromagnetic induction. He was very poor growing up and had to educate himself. He was able to as a apprentice to a book seller. He slowly made his way to the top by gaining access to the Royal Society. When he turned 40 he discovered electromagnetic induction.

• Biopic on Michael Faraday

Faraday’s Law •

Faraday’s Law • The electromotive force is in units of voltage. It is the induced voltage because of a moving magnetic field creating a current within a conductor. • For a circuit connected to any wire with a magnet going through loops, we use the EMF as the voltage.

• worksheet • Pg 592: #2, 3, 4, 5, 23