MEDI 11002 Lecture Notes - Lecture 4: Electromagnetic Induction, Flux Linkage, Electric Potential
CHAPTER 4 – GENERATING ELECTRICITY
Magnetic flux and induced currents
- Symmetry suggests that if an electric current creates a magnetic field, it should
be possible to use a magnetic field to create a current
- It is relative movement between the field lines and the loop that induces a
current in a conducting loop
- Magnetic flux is defined as the product of the magnetic field and the
perpendicular area over which it is spread:
Φ = B x Acosθ is also called the magnetic field strength
- Any way of changing the magnetic flux through a loop induces a current in the
loop. The greater the rate of change of flux, the greater the current.
Induced EMF: Faraday’s law
Faradays Law - A law stating that when the magnetic flux linking a circuit changes,
an electromotive force is induced in the circuit proportional to the rate of change of
the flux linkage.
- Faraday found that the EMF induced in the loop was dependant only on the rate
of change of magnetic flux through the loop
Faraday's law of induction is a basic law of electromagnetism predicting how a
magnetic field will interact with an electric circuit to produce an electromotive
force (EMF)—a phenomenon called electromagnetic induction.
- Total EMF is given by;
- As a conductor moves perpendicularly to a magnetic field, work is done on the
moving charges to produce a potential difference across the wires.
- This potential difference appears as an induce EMF in any loop in which the flux
is changing
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Document Summary
Symmetry suggests that if an electric current creates a magnetic field, it should be possible to use a magnetic field to create a current. It is relative movement between the field lines and the loop that induces a current in a conducting loop. Magnetic flux is defined as the product of the magnetic field and the perpendicular area over which it is spread: is also called the magnetic field strength. Any way of changing the magnetic flux through a loop induces a current in the loop. The greater the rate of change of flux, the greater the current. Faraday(cid:495)s law - (cid:498)a law stating that when the magnetic flux linking a circuit changes, an electromotive force is induced in the circuit proportional to the rate of change of the flux linkage. (cid:499) Faraday found that the emf induced in the loop was dependant only on the rate of change of magnetic flux through the loop.
