Electromagnetic Induction

When is an emf induced?

When there is a change in flux linkage as a conductor passes through a magnetic field

What is flux linkage? + equation?

Magnetic flux x the number of turns in a coil

N(flux) = (BA)N

How do you find magnetic flux linkage if the magnetic field isn’t perpendicular to the field lines?

N(flux) = BAN cos0

Faraday’s Law

The induced emf is directly proportional to the rate of change of flux

emf = change in flux linkage/time

How can you increase emf induced?

Increasing the number of turns or the change in flux over time

Lenz’s law

The induced emf is always in a direction that opposes the change that caused it

Faraday and Lenz’s law combined

-(change in flux linkage/time)

How do you use the LHR when finding the direction of the emf?

Thumb in the direction opposite to the motion of the conductor relative to the magnet

First finger = B

Second finger = induced emf