5/02  Copies of the solutions to all five Tests 
      from Spring 2007 are now available at the 
      Noble Library Copy Center.

3/09  Midterm warning grades were sent out this
      Friday.  We sent midterm E warnings to anyone
      with a midterm average less than 50 and
      midterm D warnings to anyone with a midterm
      average between 50 and 60.  In figuring the
      midterm averages we did not drop a test.

      If you get a midterm warning, you should
      see your TA to make sure that all your grades
      are entered correctly and to discuss how you
      might plan to improve your grade over the
      second half of the semester.  To see grade
      scales from previous semesters, please see
      HOW TO FIGURE YOUR FINAL GRADE on our course
      web page.  Thanks. GBA

3/08  A copy of the solutions to Test 2 is now
      available at the Noble Library Copy Center.

2/22  The lecture for Mon 2/26, on Current and 
      Resistance, includes an abnormally large 
      number of definitions.  I have provided
      a copy of those definitions for you on our
      class website.  Please download those
      definitions and bring them with you to
      lecture on Mon 2/26.  Thanks. GBA

2/12  A copy of the solutions to Test 1 is now
      available at the Noble Library Copy Center.

1/30  The Old Tests (with Solutions) are now available
      in the Noble Library Copy Center.

1/29  Practice PRS grades from lecture 6 on MON 1/29
      are now available.  Please check to make sure
      that your PRS grades are being recorded.  If
      you are not registered, your PRS grade will be
      zero.  Thanks. GBA

1/26  Friday after class one student pointed out a
      misprint in the turn-in problem E1.  The
      correction has now been made and the correct
      version is repeated here (an x was omitted
      from the numerator of the expression in part 
      (a)). I apologize for any confusion this
      might have caused.  GBA

E1.  A positive charge +q is located on the postive x-axis
      at x = +a.  A negative charge -q is located on the 
      negative x-axis at x = -a.  
      (a) Find a general expression for the total electric 
          field strength at all points on the x-axis to the 
          right of x = +a.  Show that your expression is
          equivalent to 4akqx/((x^2-a^2)^2).   (5 points)
      (b) Show how to use the binomial expansion to find
          an approximate expression for the same field
          strength which is valid for x >> +a.  Show two 
          terms in your expression.  Why is it often
          said that the field of a dipole, far from the
          dipole, "goes like" 1/(r^3)? (15 points)

  This problem is due in your recitations on the 29th
  and 30th.  Thanks. GBA

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