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Unformatted text preview: Exam III, vers. 0001 - Physics 1120 - Fall, 2007 NAME (print legibly, please)__________________________________________ Student ID #__________________________________________________ TAs Name (Circle one! ): Edwin Widjonarko, Craig Hogle, Mike Mullan, Mike Hermele, Naresh Sen Starting time of your Tues recitation (write time in box: 9am, noon, 1pm, etc) Please do not open the exam until you are told to. Your exam should have 12 pages, numbered 1 thru 12. This exam consists of 18 multiple-choice questions worth 75 points total, and two multipart long-answer questions worth 25 points total. Fill in the bubble sheet with a #2 pencil. PLEASE follow all directions carefully . Remember to circle your TA's name above. Print and bubble in your name on the bubble sheet. Print and bubble in your student Identification Number. Print and bubble in your Exam version, 0001 or 0002, in the upper left of your bubble sheet in the area marked 1234. Erase mistakes as thoroughly as possible. Ask for a fresh bubble sheet if you fear you cannot thoroughly erase mistakes. After you begin, be sure to neatly print your name and ID on the long answer question pages. At the end of the exam, check that you have filled in the first 18 questions on the bubble sheet, with only one bubble filled in for each question. I have read and followed the instructions above. Signature______________________________________________ Possibly Useful Constants and formulas: 1eV (electron-Volt) = 1.6 10-19 J. Biot-Savart law: d B = Ampere s Law: 1 Ver 0001 I 4 d L r 2 r B d L = I thru 1. A 3V battery is connected in parallel with a 2 and a 4 resistor, as shown. What are the magnitudes of the potential differences between the points shown? A) V ab = 0 V, V bc = 3 V, V ad = 3 V B) V ab = 0 V, V bc = 2 V, V ad = 1 V C) V ab = 0 V, V bc = 1.5 V, V ad = 1.5 V D) V ab = 3 V, V bc = 4 V, V ad = 2 V E) V ab = 3 V, V bc = 2 V, V ad = 1 V ab are two points along the same wire, so the potential difference must be zero. bc and ad are connected to the battery directly, so their potential difference must coincide with the potential difference across the battery. 2. In the circuit shown, the resistors R 1 and R 2 initially have the same resistance. If the resistance R 2 is now steadily decreased, how does the current through R 2 (i 2 ), the voltage across R 2 ( V 2 ) and the power dissipated in R 2 change? A) i 2 increases, V 2 increases, power dissipated in R 2 increases B) i 2 decreases, V 2 decreases, power dissipated in R 2 decreases C) i 2 decreases, V 2 does not change, power dissipated in R 2 decrease D) i 2 increases, V 2 does not change, power dissipated in R 2 increases E) i 2 increases, V 2 decreases, power dissipated in R 2 does not change If R 2 decreases, the current through it will increase as the voltage through it, equal to the voltage of the battery, remains the same. The power, being U 2 /R, will...
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- Spring '08
- Physics, Magnetic Field, Resistor, Electrical resistance