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Unit 3 Electricity

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Magnetic Field, Currents & Plasmas Physics 5h Students know changing magnetic fields produce electric fields, thereby inducing currents in nearby conductors – PowerPoint PPT presentation

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Title: Unit 3 Electricity


1
Unit 3 Electricity Magnetism Magnetic Field,
Currents Plasmas
  • Physics 5h
  • Students know changing magnetic fields produce
    electric fields, thereby inducing currents in
    nearby conductors
  • Physics 5i
  • Students know plasmas, the fourth state of
    matter,
  • contains ions or free electrons or both and
    conduct electricity

2
Magnets
  • All magnets have a MAGNETIC field around them, at
    ALL times

3
Magnets
  • Static If a magnet is NOT moving it only has a
    magnetic field
  • Moving If a magnet is moving it has BOTH a
    magnetic field AND an electric field

4
Magnetism
  • It is the force of attraction or repulsion of a
    magnetic material due to the arrangement of its
    atoms, particularly its electrons.
  • All magnetic phenomena result from forces between
    electric charges in motion.

5
Magnetic Field
  • The region where the magnetic forces
  • act is called the magnetic field

6
Magnetism Video
  • http//glencoe.mcgraw-hill.com/sites/dl/free/00787
    78069/161383/00050755.html

7
Magnetic Domains
  • Magnetic substances like iron, cobalt, and nickel
    are composed of small areas where the groups of
    atoms are aligned like the poles of a magnet.
    These regions are called domains. All of the
    domains of a magnetic substance tend to align
    themselves in the same direction when placed in a
    magnetic field. These domains are typically
    composed of billions of atoms.

8
Earth is a magnet
  • Earth exerts magnetic forces and is surrounded by
    a magnetic field that is strongest near the North
    South magnetic poles.

9
We use the Earths magnetic field to find
direction
  • The needle of a compass always points toward the
    magnetic south pole
  • We call this direction NORTH (remember,
    opposites attract)

10
Electricity Magnetism-how are they related?
  • When an electric current passes through a wire a
    magnetic field is formed.

11
What is an electromagnet?
  • When an electric current is passed through a coil
    of wire wrapped around a metal core, a very
    strong magnetic field is produced. This is called
    an electromagnet

12
How can you produce electric current from magnets?
  • By moving a magnet through a wire that is coiled
    or in the form of a loop.

13
What are electric motors?
  • An electric motor is a device that changes
    electrical energy into mechanical energy.

14
Current Electricity
  • It is different than static electricity in that
    static electricity is stationary or collects
    charges on the surface of an object, whereas
    current electricity has electrons flowing very
    rapidly through a conductor.
  • Current electricity has electrical pressure or
    voltage.
  • Electric charges flow from an area of high
    voltage to an area of low voltage.

15
There are some similarities between the flow of
water in a pipe and the flow of electric current
through a circuit
16
Plasmas
  • Plasmas are made up of free electrons and ions of
    the element ---gt charged particles
  • Therefore, they are electrically conductive.
  • Plasmas do not have a definite shape.
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