Electromagnetic Induction
Electromagnetic induction is the production of electric current by a changing magnetic field. Discovered by Faraday, this principle underlies generators, transformers, and electric motors.
What You Need to Know
Key Concept Diagram
Faraday's law: a changing magnetic flux induces an electromotive force (EMF) in a conductor
The induced current opposes the change causing it (Lenz's law)
Generator: kinetic energy converted to electrical energy using electromagnetic induction
Transformer: changes voltage using two coils and electromagnetic induction; V1/V2 = N1/N2
Key Vocabulary
Electromagnetic induction
The production of an electric current by a changing magnetic field
Magnetic flux
A measure of the amount of magnetic field passing through an area
EMF (electromotive force)
The voltage produced by electromagnetic induction in a conductor
Transformer
A device that uses electromagnetic induction to change the voltage of alternating current
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
What causes electromagnetic induction?
Question 2
Lenz's law states that the induced current:
Question 3
A transformer has 100 turns in the primary coil and 500 turns in the secondary coil. If the input voltage is 20V, what is the output voltage?
Key Concepts Summary
- ●Faraday's law: a changing magnetic flux induces an electromotive force (EMF) in a conductor
- ●The induced current opposes the change causing it (Lenz's law)
- ●Generator: kinetic energy converted to electrical energy using electromagnetic induction
- ●Transformer: changes voltage using two coils and electromagnetic induction; V1/V2 = N1/N2