General College Physics

Wisconsin Lutheran High School

Week 27 (Feb. 26 - Mar. 1)

Reading: Direct current circuits (Chap. 28)

Key Topics: electromotive force, kirchoff's circuit rules, resistors in parallel and series, ammeters and voltmeters, household wiring

Laboratory: This week, we will learn (i) how to draw simple electronic circuit diagrams, and (ii) how to analyze electronic circuits using Kirchhoff's rules. We will use an adjustable DC power supply (0 - 6 Volts, 1 Amp), assorted resistors, a tungsten filament light bulb, and two digital multimeters that can measure electric potential (volts), current (amps) and resistance (ohms). The lab consists of three parts; these parts are described in detail in the DC Circuits laboratory . Here is a brief summary of the three parts. I'd recommend doing A and B in order, but part C can be done anytime.

Ohm's law for a resistor. You will measure the current, I, passing through a resistor when a voltage V is applied across the resistor. Select a resistor of about 1000 Ohms. Be sure to set up your multimeters correctly so that one of them measures the voltage across the resistor (it acts as a voltmeter) and the other is in series with the resistor (it acts as an ammeter). Once you collect several data points (the more the better), make a plot of V vs. I. (Put V on the vertical and I on the horizontal axis) Is your data linear? If so, what is the slope? Is the slope equal to the resistance? There is a slight complication here: not all of the current measured by your ammeter is actually going through the resistor; a small portion of the current is being diverted into the voltmeter, which is in parallel with your resistor. How does this affect your measurements? In particular, are you over (or under) estimating the current passing through your resistor? And how does this affect the slope of your graph derived from your measurements?
Ohm's law for a tungsten filament: Repeat the previous measurements, but now use a small tungsten filament light bulb. To avoid burning out the bulb, you should put a resistor (try 50 or 100 Ohms) in series with the light bulb. The light bulbs are rated at 150 mAmp, so do not apply more than about 125 mAmps or they will burn out. Again, plot V vs I for your filament bulb. Is your plot linear? What does this imply? Finally: for the tungsten filament, plot the power P as a function of the current I. This is the rate of heat generation in the tungsten filament (in joules per second). P can be calculated from the Joule heating formula: P = I V.
Resistors in series and in parallel: Now we will use a multimeter as an ohm-meter. Turn the knob to the appropriate setting. Select three resistors between 10 and 90 ohms. First, measure the resistance of each by itself. Does your reading correspond to the color code on the resistor? Second, put the resistors in series and measure the resistance. Is it what you'd expect? Finally, put the resistors in parallel and measure the resistance. Is it what you'd expect?

General College Physics

2022

Return to course website.

Course syllabus

Physics: The world around us is in a state of constant change: the sun and moon rise and set, waves crash, mists rise, rain falls, fires burn, rocks form, and mountains crumble. Amidst all of these changes, there are certain patterns; there is a discernible order. In other words: the stars, the seas, the clouds, the rocks, and the earth itself each seem to have a particular nature. Physics is the careful study of the natures of things. In fact, the word physics literally means "natures" in the Greek language.

Course overview: General College Physics is a year-long introductory course for advanced (typically junior or senior level) students at Wisconsin Lutheran High School who want to better understand the natures of the things we see around us. It is a dual-credit course offered at Wisconsin Lutheran High School in collaboration with Wisconsin Lutheran College. For a detailed overview of the topics we will be covering, refer to the course website (www.greatphysics.com) and the tentative calendar on the following page. Emphasis on theoretical topics, careful thinking, laboratory experiments, and problem solving makes this course challenging. My aim is to help you succeed in this course, and to have fun while learning physics. So please do not hesitate to contact me with any problems you may run into this semester!

Advanced Placement credit: While this is not designated as an AP course, students students have successfully taken the AP Physics test at the end of the year for college credit.

Course textbook: The course will be organized around a book: the Pocket Guide to accompany Physics for Scientists and Engineers (4th edition) by Serway. (I’ll call this PSE for short.) I would highly recommend obtaining a copy of this book. It is inexpensive, compact, and well-written. It will make a very handy addition to your home science library. If you don't want to buy it, I will have copies to loan out for the semester.

Course time and location: The course meets every day (Monday through Friday) during the academic year from 2:16 until 3 pm in WLHS 223—in the science wing on the first floor of WLHS. On late start days (such as Wednesdays) the course begins at 2:24.

Professor: Dr. Kuehn from Wisconsin Lutheran College (WLC) is the professor for this course. Contact info: kerry.kuehn[at]wlhs.org

Teaching Assistant contact info: The Wednesday course sections (beginning in September) will be overseen by two teaching assistants. Alyssa Ebeling and Zeke Micheel are upper-level physics majors from Wisconsin Lutheran College. Here is their contact info: alyssa.ebeling[at]wlc.edu, ezekiel.micheel[at]wlc.edu

Course websites: In addition to the course information provided through WLHS’s OnCampus system, we will be also using a website I’ve designed for this course: www.greatphysics.com/WLHS2/

Homework exercises: I will assign weekly homework problems. These are designed to deepen your understanding of lecture material and to prepare you for the quizzes and tests. I do not intend to grade your homework solutions; I will merely give you credit for handing in your best attempt by the due date. Please refer to the late work policy for more details.

Laboratory exercises: Some of our weekly assignments will include laboratory work. Labs will typically take up at least two class periods. Your laboratory notebook pages must be submitted by the assigned due date. More details about the required format and expectations will be discussed before the first laboratory period. You will need to order/purchase a dedicated laboratory notebook. Here are guildlines on what to include in your laboratory notebook.

Quizzes: We will have in-class quizzes almost every week on Monday. To prepare for quizzes, you should read the assigned book chapter (at least once), review the lecture material, complete all of the homework problems, and review the homework solutions.

Tests: We will have a midterm exam before the end of the first (and third) quarters and a comprehensive final examination before the end of the second (and fourth) quarters.

Software: Logger Pro 3.15 Is an excellent data analysis software package. Download for Wndows 10, 8.1, 7, and for macOS 10.14, 10.13, 10.12, 10.11, 10.10. For more details on how to download and install Logger Pro click here.