EMI - Introduction to Electromagnetic Induction

Electromagnetic Induction

Introduction

In the last unit we saw how a current carrying wire can produce a magnetic field. This astounding correlation led to great advances in technology like electric motors. What we are studying in this unit is even more mysterious, but just as useful. Ørsted's discovery led to a somewhat mirrored revelation by physicist and chemist, Michael Faraday. Faraday used Ørsted's discovery to create one of the world's first electric motors. Over the years, his experimentation with similar devices led him to discover that not only can electric currents produce magnetic fields, but by changing magnetic fields in loops of wire, you can create electrical currents! Faraday's discovery of electromagnetic induction led to the creation of electric generators, which now provide us with almost all of the electricity we use in our homes, schools, and businesses.

Essential Questions

1. How do electrical power plants produce electricity?
2. How is the working of an electrical generator related to the working of an electric motor?
   

Key Terms

1. Electromagnetic induction - The process of inducing a current in a conducting loop by changing the magnetic field through the loop.
2. Magnetic flux - The perpendicular component of a magnetic field passing through a loop of given area.
3. Faraday's Law - The strength of the induced emf in a conducting loop is directly proportional to the change in magnetic flux and inversely proportional to the time of the change.
4. Lenz's Law - A current produced by an induced emf moves in a direction so that its magnetic field opposes the original change in flux.
5. Electric generator - A device that converts mechanical energy into electrical energy.
   

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