Nota Bene: This is by no means a complete or comprehensive review.
These are just random items that came to my mind that seemed helpful.
With that in mind, on with the midterm review...
Midterm Exam Information
|Date & Time
||2/29/00 at 5pm
Guide to the Lab Midterm Exam
What it's going to be like...
- The exam will cover Experiments I-V only.
- The midterm is similar to the previous
midterms... your best preparation for it is, without a
doubt, reviewing the old exams. The old exams are available
at: http://physics1.usc.edu/Undergraduate/Labs/135b/. As usual, pay particular attention to the exams going back to Spring 1998.
- The exam is closed book but most important formulas will
be given (but not the trivial ones like V=IR!).
- The exam is scheduled for 2/29/00 in THH 201
- The lab written exam is setup as follows:
- You will have 1 1/2 hours to finish
approximately 8 questions.
- There will definitely be questions on:
- DC Circuits and the various elements therein
- Ammeters and Voltmeters (and how to use them)
- Diodes and 1/2-wave rectifiers
- Equipotential Fields
- AC Circuits
- There is an equal mix between theory and computation; be
prepared to look at familiar ideas in new settings.
Also, this exam is probably more on the harder side so
be sure to study hard!
What you should know for the midterm...
Note: Click on the link for the associated quiz (with
- Introduction to Electric Circuits and Measurements -- Lab 1
- Review the different circuit element symbols (Fig. 3 on
- Know the properties of an ideal ammeter and voltmeter
(ideal ammeter offers 0 resistance whereas an ideal
voltmeter has infinite resistance; why?)
- How are they placed in circuits? Ammeters in
series and voltmeters in parallel (see p. 6)
- Make sure you understand how you setup and used the one
and two battery circuits (pp. 7-8)
- Know how to measure voltages across elements (e.g.,
across the bulb) or currents in a circuit (ammeter is
placed in series, i.e., before or after the circuit element)
- Mapping the Electro-static Field -- Lab 2
- Know the relationship between E & F (E = F/q)
- Know the relationship between V & E (V = Ed)
- Review the mechanical analogy between Voltage and
Gravitational Potential Energy (V=W/q; W=DPE; V=DPE/q)
- Be sure you understand the gravitational analogy (and
especially make sure you understand the quiz questions &
also Fig. 3 on p. 18)
- How do E & V work in electrophoresis?
- How does the Faraday Ice Pail work and what does
it's equipotential field look like (review the diagrams
in your answer book or the lab notes to the left)
- Where was the electric field strongest in the Ice Pail?
the weakest? Why?
- DC Circuits -- Lab 3
- Recall Ohm's Law and the various derived formulas (e.g.,
V=IR; P=IV; etc. -- more listed in the lab notes
for this lab)
- Make sure you understand Kirchoff's rules (the node rule
and the loop rule); review them in the manual or in the
- Understand the difference between ohmic and non-ohmic
materials (constant resistance vs. variable resistance;
linear I vs. V graph versus non-linear I vs. V graph; etc.)
- Be aware of the difference between Ravg and
Rdynamic (see the lab notes). Make sure you
know how they're calculated (see especially Fig. 1 on
- From p. 25 of the manual, what is Imax? What
is the significance of it? How do you compute it?
- Review resistance in series and in parallel; current in
series and in parallel; voltage in series and in
parallel (see the lab notes for these formulas -- be
sure to understand the formulas and make sure you're
able to apply them, too)
- Some things to consider: how did you actually connect
the resistors in series and in parallel? How did you
measure V & I in the various configurations (for this
part, review pp. 32-33 carefully)
- AC Circuits -- Lab 4
- What is the power source in DC and AC circuits?
Batteries or DC power supply in DC and the function
generator in AC. What is the difference between
alternating current and direct current? (See Fig. 1 on
p. 38 for this guy)
- Be very sure you completely understand the difference
between peak current, peak-to-peak current, DC offset,
and RMS current (see the lab notes for all of these).
Where is RMS current applicable (sine waves ONLY!)?
When is Irms = Io/sqrt(2) (see
p. 39)? How do you get the period of a wave? How about
- For AC circuits, which values are used in the application
of Ohm's and Kirchoff's laws? (the RMS values only).
What values does the multimeter read?
- Diodes -- Read ALL of p. 41!
- Also, read pp. 51-53. Know how diodes work, what the
output looks like, what it does in the 1/2-wave
rectifier circuit (and how). In essence, make sure you
understand what a diode does and how the oscilloscope
output looks before and after putting the diode in the
circuit (and, while you're at it, consider how the
output changes when you mess with the diode or the
circuit, as you did in question 4.3.2)
- Electronic Filters -- Lab 5
- Know what a capacitor is and what it's electric field
looks like (see also Lab II for this one)
- How do V & I vary in a charging capacitor (see Fig. 3 on
p. 65)? What is the time constant t? What is it's significance in
terms of the charging/discharging capacitor (see Fig. 3
- Make sure you know how the period, T, is related to the
frequency, f, and the angular frequency, w (T = 1/f; 2pf=w)
- Review the lab notes and be sure to understand the logic
of the derivations of the different values we got in
- What is I & V for a capacitor in an AC circuit? Does
current lead V by 90o (see the quiz or the
lab notes if you're not sure)?
- How does the capacitor act as a filter (see p. 67 for
- For this one, I'd really make sure I understood
the difference between high- and low-pass filters
(memorize the table from the lab notes for this one)
- What does a line filter do? How about a band-pass
filter? Review the lab notes and your answer manual for
this one! How did you make the composite filters (see
p. 70)? How would you actually build this in practice
(i.e., all at once, one after the other, etc.?)
- Make sure you review all the formulas and understand what is
what in the main ones enough to be able to use them (e.g., does
the R in lab 3 correspond to Ravg or Rdynamic)
- Remember to keep track of units during any calculations; perform
unit conversions with care and keep an eye out for order of
magnitude errors (e.g., if you're checking the line filter, is
it for 60 Hz or 60 kHz?). Also, be VERY careful with the
polarity (see lab 1's notes for checking polarity)
- Finally, work quickly but carefully... and the neater the work,
the easier it is on the grader. If you're unsure of the answer
but are sure of your reasoning leading up to the answer,
go ahead and explain what you were trying to do or what you
know. Often, that'll get you at least some partial credit (if
your reasoning is correct, that is!). Always try to write
down the correct units at all stages and check your
intermediate results to make sure it makes sense. And, most
importantly, remember to take a deep breath and relax! In the
big scheme of things, this really isn't all that much... just
your whole, entire future, is all...
What you should bring to the written exam...
- Your calculator (don't leave home without it!)
- Ruler or straight-edge
- A pen or pencil (depending on how masochistic you are...)
Please direct all omissions, suggestions, or errors to:
Ricky J. Sethi <firstname.lastname@example.org>
Last modified: Sun Apr 16 19:48:30 2000