Lesson 1443 of 1524
Electromagnetic Induction
The induced emf in a closed loop due to a change in magnetic flux through the loop is known as Faraday’s law.
Practice this chapterThe induced emf in a closed loop due to a change in magnetic flux through the loop is known as Faraday’s law. The direction of an induced emf always opposes the change in magnetic flux that causes the emf, a result known as Lenz’s law
An induced emf from Faraday’s law is created from a motional emf that opposes the change in flux The units for magnetic flux are webers, where 1 Wb = 1 T · m 2
Lenz’s law — direction of an induced emf opposes the change in magnetic flux that produced it; this is the negative sign in Faraday’s law. Faraday’s law — induced emf is created in a closed loop due to a change in magnetic flux through the loop. induced emf — short-lived voltage generated by a conductor or coil moving in a magnetic field. magnetic flux — measurement of the amount of magnetic field lines through a given area.
Worked example
What does “Lenz’s law” mean in Electromagnetic Induction?
- 1Use the wording this chapter gives for Lenz’s law.
- 2The book says: direction of an induced emf opposes the change in magnetic flux that produced it; this is the negative sign in Faraday’s law.
- 3Do not use the meaning of Faraday’s law. That term means induced emf is created in a closed loop due to a change in magnetic flux through the loop.
Result: direction of an induced emf opposes the change in magnetic flux that produced it; this is the negative sign in Faraday’s law
Why. That is the meaning this chapter gives for Lenz’s law.
Do not swap Lenz’s law and Faraday’s law. Lenz’s law means direction of an induced emf opposes the change in magnetic flux that produced it; this is the negative sign in Faraday’s law. Faraday’s law means induced emf is created in a closed loop due to a change in magnetic flux through the loop.
Practice margin
This chapter
A fresh set from this chapter only. Choose 10 or 20. Multiple choice and fill-in, with no repeat inside the set.