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Lectures
Lecture: 22 (iq20)
Microscopic picture of a circuit
1. A simple circuit: Macro vs
micro descriptions
2. Drude model and drift velocity
3. Mechanical battery and steady decreasing surface
charge density.
4. Steady state of a current flow in a circuit
a. One loop: i maintains the
same value throughout
b. Node: iin=i1+i2
5. Examples
a. Loop equations and node equations Kirchhoff’s rules.
b. Simple circuit
c. Example with a simple series connection
d. Example with a simple parallel connection
e. Example with 4 identical bulbs
Announcement:
Bookmark the official website
of our homepage:
http://www.ph.utexas.edu/~itiq/instructors/chiu/
This site has the present
semester lesson plan, including the location of each of our midterms.
Midterm 2: Class average
is 58.
o
Reminder: How to
determine the letter grade you made for this midterm?
o
Find you scaled
score which is located near the bottom of the grading page.
o
Two letter grades
for each exam:
§ letter grade-1 based on % cutoffs.
§ Letter grade-2 based on scaled score cutoffs.
o
The letter grade you have made for this exam
is the higher of the two letter grades, if there is a difference.
o
Those have done
below 45, you need to look for ways to improve your performance (pay attention
to the physics content and the logics of each homework problem)
o
I encourage you to
work out those problems you have missed (without looking at the solutions).
o
Come to talk to
me during my office hours, MWF 1:30-2:00, 3:00-3:30 or other time by
appointment. Rework missed exam
problems. Bring your work when you come.