Presentation on theme: "ELECTROMAGNETIC INDUCTION Magnetism to electricity."— Presentation transcript:
ELECTROMAGNETIC INDUCTION Magnetism to electricity
E LECTROMAGNETIC I NDUCTION The production of electricity by magnetism is called electromagnetic induction. Faraday’s law of electromagnetic induction states: A changing magnetic field in the region of a closed-loop conductor will induce an electric current.
EMF When a wire moves through a magnetic field not only is a current induced, but an electric potential difference is also induced. This induced electric potential difference is often called the electromotive force (emf). An emf and current can only be induced in a wire if the wire moves perpendicular to the magnetic field
I NDUCED C URRENT Faraday discovered that three factors influence the magnitude of the emf and induced current in the wire. These factors are: 1. velocity of the wire as the velocity increases, the emf and induced current increase 2. strength of the magnetic field as the strength of the magnetic field increases, the emf and induced current increase 3. length of the wire in the external magnetic field As the length of the wire increases, the emf and induced current increase Use pHet Simulation to demo
L ENZ ’ S L AW Lenz’s law : An induced current and emf are in such a direction as to oppose the change that produced them. In other words, the induced current will create a magnetic force that acts on the wire. The direction of this force is opposite to the direction of the wire’s velocity.