Transcript class slides for Chapter 17

17
Electric Charge and
Electric Field
Lectures by James L. Pazun
Copyright © 2012 Pearson Education, Inc. publishing as Addison-Wesley
Goals for Chapter 17
• To study electric charge, conductors, and
insulators.
• To understand Coulomb’s law and solve some
example problems.
• To understand electric fields.
• To calculate electrical forces.
• To map out electric field lines
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Electrical charges are all around us.
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Exploring the nature of electrical charge - Figure 17.1
• Plastic, silk, rubber, glass and fur can reveal fundamental
behaviors of charge.
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Atomic charge arrangements – Figures 17.2, 17.3
• Protons (+) and electrons
(-) account for atomic
charges.
• Electrons move, protons
don’t.
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Charge movement by conduction – Figure 17.4
•Direct contact
•Charge moves through a
conductor.
– Metals are good
conductors
– Non-metals are most
often not
• Discuss insulators.
•Discuss semiconductors.
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Charging by induction – Figure 17.5
•If attracted or repelled, the electrons inside an object may
be polarized.
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Static effects even uncharged objects – Figure 17.6
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Polarization (the paper and the comb) – Figure 17.8
Induced
charges
are
present in
the
everyday
examples.
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Polarization determines induced charge – Figure 17.7
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How Coulomb measured the force – Figure 17.9
• Read
through the
text on
pages 552553.
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Electrical force – Examples 17.1 and 17.2
• Refer to the problem solving strategy on page 554 then try
examples 17.1 and 17.2.
• The problems build complexity in layers be sure to do these
two!
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Forces are additive – Example 17.3
Refer to the worked problem on page 556 and figure 17.11.
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Forces are additive even if non-linear – Example 17.3
Refer to the worked problem on page 557 and figure 17.12.
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Mapping out the electrical field – Figures 17.14-15
Moving the test charge can allow forces to be measured.
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Force causes acceleration – Example 17.5
Refer to the worked problem on page 559 and figure 17.16.
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Calculating the electric field – Example 17.6
Refer to the worked problem on page 561 and figure 17.17.
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The field around a dipole – Example 17.7
Refer to the worked problem on pages 562-563 and figures
17.18 and 17.19.
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The electric field is mapped – Figures 17.21-17.22
Refer to the characteristics at the bottom of page 563.
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The field formed related to the electrode – Figure 17.23
Refer to the text in the middle of page 564.
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