12/8 Test 5 Solutions as well as the three "Summary Sheets" from the Notes are now available at the Noble Library Copy Center 12/6 WARNING!! TEXT MISLEADING ON PAGE 949 Equations (35-31) and (35-32) on page 949 of our text are potentially misleading. Equation (35-31) is for instantaneous power, i.e. power as a function of time, and equation (35-32) is for maximum power. The right equation for average power (which is almost always the value given in any problem) is <P> = I(4piR²). Example 35-5 is especially misleading since they use a 100 W bulb and treat the problem as if this 100 W was the maximum power of the bulb, when in any reasonable case, the 100 W would be the average power. The book returns to sanity in HW problems 22, 31 (not assigned), and 32. In each of these problems the book gives an emission power which in each case is an average power. 12/1 Message to Tuesday Recitations Due to the missed quiz at the first recitation meeting, the Tuesday Recitations WILL HAVE A QUIZ during the last recitation meetings on Dec 7th. This will make 14 quizzes for each of the Mon and Tues Recitations. 11/29 Message to Mon 8:40 and 9:40 Recitations: Due to an error in the key (for which I apologize) Multiple Choice #4 was graded incorrectly. Please return your test paper to your TA for correction. Thank you. 11/24 A copy of the solutions to Test 4 is available at the Noble Library Copy Center. 11/12 There will be a nighttime help session at 7PM in PSF-101 on Monday 11/15. No test hints will be given, no new material will be covered, and I will not do HW problems. I WILL answer your questions about concepts that you do not understand. EXTRA OFFICE HOURS - Tues 11/16 2:30 - 4:30 PSF-430 11/8 In the HW for Mon Nov 8 (HW assignment #30) make the following change: Drop problem 14 and add problem 15 (Chapter 32). In the reading for Chapter 32, add Section 1 through equation 32-1, and Section 3, stopping at Hysteresis on page 872. 11/3 In the HW for Wed Nov 3 (HW assignment #28), make the following change: Drop problem 40 and add problem 44 (Chapter 31). 11/2 A copy of the solutions to Test 3 is available at the Noble Library Copy Center. 10/22 There will be a nighttime help session at 7PM in PSF-101 on Monday 10/25. No test hints will be given, no new material will be covered, and I will not do HW problems. I WILL answer your questions about concepts that you do not understand. EXTRA OFFICE HOURS - Tues 10/26 1:30 - 3:30 PSF-430 10/19 My usual Friday office hour, this week only, will be moved to Thursday from 2:30 - 3:30 in PSF-430. 10/11 A copy of the solutions to Test 2 is available at the Noble Library Copy Center. 10/4 Message to Mon 840 and Mon 940 Recitations: Dan forgot to record the grades of the HW and quiz papers that he returned to you today. Please save those papers and show them to him next Monday so that your grade can be properly recorded. Thanks. 10/1 There will be a nighttime help session at 7PM in PSF-101 on Monday 10/4. No test hints will be given, no new material will be covered, and I will not do HW problems. I WILL answer your questions about concepts that you do not understand. EXTRA OFFICE HOURS - Tues 10/5 2:30-5:00 PM 9/21 ANNOUNCEMENT #1 In HW #12 for 9/22 make the following change: Drop problem 61 and add the following problem: A thin, spherical, conducting shell of radius R is mounted on an insulated support and charged to a potential -V. An electron is fired from point P a distance r from the center of the shell with an initial speed v_0, directed radially inward. What is the value of v_0 chosen so that the electron will just reach the shell? ANNOUNCEMENT #2 My office hour this Friday only (9/24) will be delayed by one hour. That is, my office hour Fri will be 3:40-4:40 instead of the usual 2:40-3:40. 9/17 A copy of the solutions to Test 1 (Yellow Test) is available at the Noble Library Copy Center 9/10 There will be a nighttime help session at 7PM in PSF-101 on Monday 9/13. No test hints will be given, no new material will be covered, and I will not do HW problems. I WILL answer your questions about concepts that you do not understand. EXTRA OFFICE HOURS - Tues 9/14 2:30-5:00 9/6 Comments on the neatness and organization of HW. It is to your advantage to make your HW as neat as possible. If your TA can follow your logic clearly, then it is more likely that you will receive the proper credit for your work on the 10 point problems. It is also to your advantage to organize your HW as clearly and as neatly as possible. This increases the likelihood that your TA will find all of the one point problems and be able to determine that you have made a "good faith attempt to solve them." Please do not simply copy down the right answer and then expect to receive credit for an attempt to solve any particular problem. Neatness and good organization is to your own advantage as well as a point of consideration for your TA and for your fellow students, whose papers are being graded at the same time as yours. Remember that your TA is grading as many as 120 HW papers per week. Homework that is EXCESSIVELY sloppy and/or disorganized, to the point of being extremely difficult or impossible to grade, will not receive credit, at the disgression of your TA. In such a case the TA will make a copy of your HW paper, in case of an appeal to the course instructor. 8/30 Monday recitations miss one meeting because of the Labor Day holiday. Several people have asked me about the HW that would have been turned in on that day. Following the rules in the syllabus, that HW will be turned in on Mon Sept 13, along with all other HW assigned through the previous Wed (Sept 8), but not yet turned in. To be explicit, on 9/13 the HW due will be the HW from 8/27, 8/30, 9/1, 9/3, and 9/8. I apologize for not making this clear in the syllabus.