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McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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ElectricityElectricity
Principles & ApplicationsPrinciples & ApplicationsEighth EditionEighth Edition
Chapter 1Basic Concepts
(student version)
Richard J. Fowler
McGraw-Hill
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McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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INTRODUCTION
• Work and Energy• Atoms• Ions• Charge
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Dear Student:
This presentation is arranged in segments. Each segmentis preceded by a Concept Preview slide and is followed by aConcept Review slide. When you reach a Concept Reviewslide, you can return to the beginning of that segment byclicking on the Repeat Segment button. This will allow youto view that segment again, if you want to.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Preview• Energy and work are interrelated terms.
• Energy can be converted from oneform of energy to another form of energy.
• W is the symbol for bothwork and energy.
work and energy.• The Joule (J) is the unit for both
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Work (W)consists of a force moving through a distance.
Energy (W)is the capacity to do work.
The joule (J)is the base unit for both energy and work.
The amount of work done equals the amount of energy used (converted).
Fifty joules of energy are required to do fifty joules of work.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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A cell converts chemical energy to electric energy.
A light bulb convertselectric energy to lightenergy and heat energy.
ENERGY CONVERSION
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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ENERGY QUIZThe _____ is the base unit of energy. joule
The symbol for the base unit of work is the letter _____ .
J
The italicized upper-case _____ is the symbol for energy.
W
Doing forty joules of work requires _____ joules of energy.
forty
A light bulb converts _____ energy into_____ energy and _____ energy.
electriclight, heat
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Review
Repeat Segment
• energy and work are closely related
• energy can be converted from oneform of energy to another form of energy
• W is the symbol for bothwork and energy
work and energy• the Joule (J) is the unit for both
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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PARTICLES OF THE
HELIUM ATOM
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Concept Preview
• Electrons are always in motion.
• Electrons and protons have an electric charge.
• Atoms contain electrons, protons, and neutrons.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Protons (+ charge)
Neutrons (no charge)
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Protons (+ charge)
Neutrons (no charge)
Electrons (- charge)
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The electrons’ orbital paths are shown by the dashed lines.
The electrons orbit around the nucleus (neutron/proton cluster).
Protons (+ charge)
Neutrons (no charge)
Electrons (- charge)
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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-The two electrons are in the same shell even though they have different orbital paths.
HELIUM ATOM
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= Neutron
= Proton
= Electron
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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= Neutron
= Proton
= Electron
Each electron stays in its own
orbital path.
HELIUM ATOM
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Preview
• Electrons are always in motion.
• Electrons and protons have an electric charge.
• Atoms contain electrons, protons, and neutrons.
Repeat Segment
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Formation Of Ions
from
Atoms
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Concept Preview
• Ions are basically charged atoms.
• A negative ion has gainedan electron.
an electron.• A positive ion has given up
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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A SODIUM ATOM
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AND A CHLORINE ATOM
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Sodium Atom
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FORMATION OF IONS
Chlorine Atom
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Sodium Ion
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FORMATION OF IONS
Chlorine Atom
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Chlorine Atom
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Sodium Ion
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FORMATION OF IONS
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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FORMATION OF IONS
Chlorine Atom
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Sodium Ion
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McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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FORMATION OF IONS
Chlorine Ion
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Sodium Ion
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McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Review
• Ions are basically charged atoms.
• A negative ion has gainedan electron.
an electron.• A positive ion has given up
Repeat Segment
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Preview
• An attracting force exists between unlike charges.
two like charges.• A repelling force exists between
• Positively-charged objects have a deficiency of electrons.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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_chargecharge
_charge__
charge
_charge
Like charges produce a repelling force.
When physically released, they repel each other.
Force Between Electric Charges
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Charged rod. (Many negative charges have been removed from the rod.)
+ + + + + --- + + + + + + + + +
+ + + + + + --- + + + + + + + +
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_ +_ +_+_+_+_+
+_+_
Uncharged ball suspended on a thread. (Equal number of negative and positive charges uniformly distributed.)
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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+ + + + + --- + + + + + + + + +
+ + + + + + --- + + + + + + + +
+_ +_ _
+++_+_ _
+_+_
Ball receives small induced charge as rod approaches. (Note clustering of like charges on ball’s surface.) Weak force of attraction develops.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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+ + +_ _ _
+ + +_ _ _
+ +_ _
+ + + + + --- + + + + + + + + +
+ + + + + + --- + + + + + + + +
More clustering of like charges and stronger attraction occurs as the rod is moved closer to the ball.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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+ +---++ --- +
+ --- + + --- +
+ --- +
+ + ---+
+ -- + + --- +
+ --- ++ --- +
+ + + + +
+ + + + + +
+ + + + +
Electrons are transferred from ball to rod when contact is made. Now, both ball and rod have a positive charge.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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+ + + + ++ + + + + ++ + + + +
+ +---++ --- +
+ --- + + --- +
+ --- +
+ + ---+
+ -- + + --- +
+ --- ++ --- +
The ball is now repelled by the rod because of the like charges on the two objects.
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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CHARGE QUIZ
Electrons have a _____ electric charge. negative
Protons have a _____ electric charge. positive
The _____ is electrically neutral. neutron
The charge of a sodium ion is _____ . positive
A chlorine ion has a(n) _____ of electrons. excess
Like charges _____ each other. repel
McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.
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Concept Review
• An attracting force exists between unlike charges.
two like charges.• A repelling force exists between
• Positively-charged objects have a deficiency of electrons.
Repeat Segment