Homework #3
Spring 2010
Read:
Chapter 22, section 22.5;
Chapter 25, intro., sections 25.1, 2, 3
Chapter 23, intro., sections 23.1 (thru mid of p. 782), 23.2 (thru p. 791, incl. Ex. 23.3)
Handouts:
Conductors in Electrostatic Equilibrium
;
Basic Ideas:
Electric Field & Gauss' Law
Conductors & Insulators
Method of Image Charges
Electric Current, Voltage, & Potential
Electrical Resistivity, Drift Velocity, & Resistance
Math Skills:
Geometry, Trigonometry, Symmetry Principles
Path Integrals of a Vector Field, Conservative Vector Fields
Learning Goals:
(Be sure you understand where and how each goal in each assignment applies to our
homework, discussion, lecture, and lab activities.)
*
Use Gauss' law along with basic mechanics and electrostatics principles to deduce the
presence or absence of electric fields and electric charge in, on, and near conductors in
electrostatic equilibrium, and to relate field strengths and surface charge densities.
*
Draw electric field lines in the vicinity of conductors in electrostatic equilibrium, and use the
geometry of those lines to compare relative electric field strengths at different locations.
*
Use the Method of Image Charges for electric charges near a conducting plane to determine
magnitude and direction of the net electric field, including induced charges on the plane.
*
Use the relationships between electric charge and electric fields to explain and calculate the
strengths of electric effects in physical phenomena discussed in lecture and your textbook.
*
Show how to determine voltage (electric potential difference) from electric field and vice-
versa using path integrals and space derivatives along with equations or graphs.
*
Determine the electric current, current density, electric field, voltage, resistivity, drift
velocity, or geometry in current-carrying conductors, given appropriate other quantities.
*
Conceptually translate an equation for electric field or potential difference as a function of
position into a graph (without doing detailed numerical calculations).
*
Show that algebraic and numerical results have correct units and are physically reasonable.
For extra practice:
Chap. 22:
Q's #Q22.10, 12, 14-17;
E's & P's #22.23, 31, 43, 46, 49
(not quizzed)
Chap. 23:
Q's #Q23.4, 8, 10, 17, 19, 20, 21
Chap. 25:
Q's #Q25.2, 3, 9-13;
E's & P's #25.3, 8, 17, 27
To be prepared for a Quiz on Wednesday-Friday, Feb. 15-19, at your 2nd weekly Discussion
#Q23.5 & 7
[Electric Field Path Integrals]
For #Q23.5, give an example to illustrate your
answer, perhaps a situation from lecture or elsewhere in your HWs.
#22.37