Transcript electricity - Montgomery College

ELECTRICITY
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The purpose of an X-ray unit is
to convert electric energy into:
ELECTROMAGNETIC ENERGY of
the x-ray beam
TYPES OF ELECTRIC
ENERGY CONVERSION
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Recharging a car
battery converts
electric energy into
chemical energy
table saw converts into
mechanical energy
Kitchen appliances
converts to thermal
energy
ELECTROSTATICS
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Matter has:
mass
form
energy
(may also
have:)electric
charge
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ELECTRIC
CHARGE
Positive and
negative
Electron and
Proton
ELECTRON AND
PROTON
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Electrons can travel from outer
shell of one atom to another
easily
Protons cannot travel easily or
at all because they are fixed in
the nucleus
THEREFORE:
ELECTRIC CHARGE IS
PRIMARILY
ASSOCIATED WITH
ELECTRONS
ELECTROSTATICS
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The study of electric charges in
stationary form.
Static electricity!!!
ELECTRIFICATION
ELECTRIFIED!!!
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An object which as too many or
two few electrons is considered
to be electrified.
“The transfer of electrons from
one object to another causes
the first object to be positively
electrified and the second
object to be negatively
electrified” page 76
CAUSES OF
ELECTRIFICATION
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Contact
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Friction
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Person to object
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Balloon
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Lightning
Induction
GROUND
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Electrically
neutral object
which acts as a
reservoir for
electric charges
COULOMB (C)
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Because the charge of an
electron is too small to
measure, a fundamental
measuring unit for electric
charge is 1 C or
6.3 x 10 to the eighteenth
power electron charges
ELECTROSTATIC LAWS
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Like charges repel
unlike charges attract
Both form an electric field
Positive field radiates outward
Negative field radiate inward
ELECTOSTATIC FORCE IS THE REPULSION OR
ATTRACTION BETWEEN CHARGES DUE TO THE
ELECTRIC FIELD
COULOMB’S LAW:
THE GREATER THE
ELECTROSTATIC
CHARGES FOR EITHER
OBJECT, THE GREATER
THE ELECTROSATIC
FORCE
COULOMB’S LAW:
THE FORCE IS
STRONGER WHEN
OBJECTS ARE CLOSER,
WEAKER WITH THE
INCREASE OF
DISTANCE
ELECTRIC CHARGE
DISTRIBUTION
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ELECTRIC CHARGES ARE
UNIFORMLY DISTRIBUTED
THROUGHOUT THE OBJECT OR
ON ITS SURFACE
ELECTRIC CHARGE
CONCENTRATION
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THE ELECTRIC CHARGE OF A
CONDUCTOR IS
CONCENTRATED ALONG THE
SHARPEST CURVATURE OF ITS
SURFACE.
ELECTRODYNAMICS
WHAT IS IT?

Study of Charges in Motion
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AKA: Electricity!!!!!!
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FLOW OF
ELECTRONS=ELECTRIC
CURRENT
THE FLOW THE ELECTRONS IS
OPPOSITE THE CURRENT
ELECTRONS FLOW EASILY
THROUGH CONDUCTORS
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Insulators impede the flow of
electrons.
Semiconductors do both!!
Superconductivity: some
material display no resistance
below a critical temperature
Four States of Electrical
Matter
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Superconductor
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Conductor
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Semiconductor
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Insulator
Electric Circuits
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Electrons flow along outer
surface of wire. When the path
is closed and resistance can be
controlled, this is known as an
electric circuit.