Chapter 22 Gausss Law Power Point Lectures for

Goals for Chapter 22 • To study electric flux • To calculate electric flux

Introduction • The movement of electrons can be shocking (pardon the pun). • If

Flux as the flow out of an imagined box • If we construct a

What happens as I change the conditions? • Consider +1 versus +2 or a

A measurement of flux will be sensitive to measurement • If we considered flux

Flux in a uniform field • Measurement of the flux for a uniform electric

If the field is not uniform—the disk • Refer to Example 22. 1 to

If the field is not uniform—the cube • Refer to Example 22. 2 to

If the field is not uniform—the sphere • Refer to Example 22. 3 to

Gauss’s Law • The expression is an alternative to Coulomb’s Law. • The nifty

Flux through concentric spheres with different radii • Consider the flux as changing the

Projecting flux through other shapes • Consider Figure 22. 12 to contemplate flux through

Effect of changing the sign of the charge • Figure 22. 14 leads us

There are practical applications • Figure 22. 17 treats excess charge as residing on

The field of a line or plane of charge • Consider Example 22. 6

A field between parallel plates of opposing charge • The capacitor is the actual

The field of a uniformly charged sphere • Consider Example 22. 9. • Figure

Charges on conductors • The electric field within a charged conductor may be found.

Experimental tests of Gauss’s Law • Regard Figure 22. 25. • A metal container

The Van de Graaff generator • The source of all the static on the

A Faraday cage blocks flow • Refer to Figure 22. 28 below. • Science-fiction

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Chapter 22 Gauss’s Law Power. Point® Lectures for University Physics, Twelfth Edition – Hugh D. Young and Roger A. Freedman Lectures by James Pazun Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Goals for Chapter 22 • To study electric flux • To calculate electric flux with Gauss’s Law • To consider the electric field of various symmetric charge distributions Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Introduction • The movement of electrons can be shocking (pardon the pun). • If you look at the girl’s hair (figure to the right), you’ll see the electrons coating each individual hair fiber and then repelling each other. • Gauss imagined a flow through a surface placed around a charge and then considered outcomes that we will study in Chapter 22. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Flux as the flow out of an imagined box • If we construct a boundary around a charge or charges, we can think of the flow coming out from the charge like water through a screen surrounding a sprinkler. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

A measurement of flux will be sensitive to measurement • If we considered flux through a rectangle, the flux will change as the rectangle changes orientation to the flow. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

If the field is not uniform—the disk • Refer to Example 22. 1 to evaluate flux through a disk. • Figure 22. 7 illustrates this example. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

If the field is not uniform—the cube • Refer to Example 22. 2 to evaluate flux through a disk. • Figure 22. 8 illustrates this example. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

If the field is not uniform—the sphere • Refer to Example 22. 3 to evaluate flux through a disk. • Figure 22. 9 illustrates this example. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Gauss’s Law • The expression is an alternative to Coulomb’s Law. • The nifty thing about being a scientist in Gauss’s day is that you got to leave your name on clever work (not to mention the nice painting). Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Flux through concentric spheres with different radii • Consider the flux as changing the radius of the sphere changes its volume. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Effect of changing the sign of the charge • Figure 22. 14 leads us to consider the effect of changing the sign of our point charge. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

There are practical applications • Figure 22. 17 treats excess charge as residing on the surface of a conductor. • Consider Example 22. 5. • Figure 22. 18 illustrates Example 22. 5. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

The field of a line or plane of charge • Consider Example 22. 6 and Figure 22. 19. • See also Example 22. 7 and Figure 22. 20. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

The field of a uniformly charged sphere • Consider Example 22. 9. • Figure 22. 22 illustrates the example. • Follow Example 22. 10. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Charges on conductors • The electric field within a charged conductor may be found. • Consider Figure 22. 23. • Follow Example 22. 11 and Figure 22. 24. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

The Van de Graaff generator • The source of all the static on the child’s hair in our introduction. • Consider Figure 22. 27 below. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

A Faraday cage blocks flow • Refer to Figure 22. 28 below. • Science-fiction movies always place alien transmitters in these to prevent them from calling for help. • Follow Examples 22. 12 and 22. 13. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley