Here are a few more conceptual questions that deal with Chapters 16 and 17, although not much specifically related to the electric fields and potentials created by charged particles.
Here's the equation sheet that you will receive for the Semester Exam. We revisited some of our past material today in preparation for the Semester 1 Final Examination. The Exam will consist of about 50 multiple choice items and a handful of problems to solve. Count on roughly 75 minutes to complete this exam, assuming we work about as fast as students in past years.
Linked below are some things that you should be able to handle: Assignment:
Does a metal cloak really provide complete shielding? I dunno. Check this out to see the answer: We navigated our way through Ch 16 P: 23, 24, 25, and 27 successfully.
Next up were equipotential lines, a way to represent an electric field. We plotted the values of the electric charges carried by the oil drops we observed. We plotted them from smallest amount of charge to largest amount of charge. Here's what we got: We noticed that all of the well-measured charges were whole-number-multiples of 1.6 x 10E-19 C. Millikan noticed that, too, back in 1910. In fact, no one has ever observed an electric charge that wasn't a whole-number-multiple of 1.6 x 10E-19 C. So this must be the amount of electric charge carried by an electron. And, to be sure, it is a negative charge. Protons carry the same amount of charge except that it is positive for protons.
You should understand our work with the Millikan Oil Drop experiment well enough to answer questions about it. Assignment:
Robert Millikan figured out how much electric charge an electron carries. We want to do the same thing today in roughly the same way. Use either of the two Millkan Simulations on the Chapter 17 web page. When you get a drop to float, record the potential that did the trick for that particular drop along with the rest of Physics II students at our Millikan Google Sheet, and get the potential as close as you can to "perfection." Then do it again for as many different drops as you can in 20 minutes.
We are now seeking to find out the amount of electric charge carried by electrons using the strategy Robert Millikan used over a century ago. In order to do that, you have to know how to find the strength of the electric field produced by two parallel metal plates that are at different potentials and which have a known separation. We also identified the forces acting on a floating, charged object, namely the electric force and the gravitational force. If the object is floating, these forces are equal to each other. Assignment:
We had a hair-raising experience today! Or, rather, quite a few of them. Let's be thankful for electric fields!
Assignment:
Today we debriefed yesterday's work concerning the potential vs position between and around parallel metal bars. Here is what we found, more or less: Of course, you may have set your power supply at a potential different from the 12 V shown above, and you may have measured potentials from low-to-high rather than from high-to-low as shown. None of that matters. What does matter is how strong the electric field is in each region. The slope is the key.
Assignment:
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Physics II
Mr. Swackhamer Scottsdale Preparatory Academy Archives
March 2020
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