Download Examination 1 for University of Arizona, ECE 220: Basic Circuits and more Exams Electrical and Electronics Engineering in PDF only on Docsity! University of Arizona Department of Electrical & Computer Engineering ECE 220 Basic Circuits Examination 1 February 8, 2001 Closed book/notes, calculators allowed. Part I: 8 questions Part II: 8 questions. Part II is worth twice as much as Part I. IMPORTANT: Write the color of your exam paper (IVORY or GREEN) on the top margin of the SCANTRON. Please mark your name and birth date on the SCANTRON answer sheet, using a #2 pencil. All information should be left justified. Also write the information below, and place your UA picture ID card on the adjacent desk where it can be easily seen. When the 9:00 bell rings, begin the examination. All work should be done on the examination paper. Allow for reasonable amounts of roundoff error, and carefully mark one choice for each problem on the SCANTRON answer sheet. e.g. 1 All answer sheets and examinations will be collected at or before 9:55. You will be asked to stop writing and hand in your papers/answer sheets. Failure to comply promptly may result in disqualification from the exam. NAME: ______________________ SIGNATURE: ______________________ 1 2 4 5 A B C D E if the answer for Question 1 is C.Please remember this number: … It will be used to post your grades in ECE 220 throughout the semester. [1] The two terminal element is assumed to be a resistor with a value of R (ohms). Using the indicated reference polarities for v and i, which is the correct set of equations for Ohm's Law and the dissipated power p? (a) v = iR p = v2/R (b) v = iR p = -v2/R (c) v = -iR p = v2/R (d) v = -iR p = -v2/R (e) None of these. [2] An analog voltmeter consists of a d'Arsonval movem with resistance RV. In normal operation, how do the (a) Vm R R < (b) Vm R R > (c) Vm R R = (d) None of these. [3] A current source is short-circuited, as shown. Which the current source? (a) The current source delivers an infinite amount of po (b) The current source delivers a fixed (non-zero) amou (c) The current source delivers zero power (d) Circuit is not valid (e) None of these. [4] A 10kV voltage can also be specified as: (a) 104 MV (b) 103 V (c) 106 mV (d) 1010 µV (e) None of these. [5] How much energy does it take to start a car engine if for a period of 1.5 seconds? (a) 5 kJ (b) 4.5 kJ (c) 4 kJ (d) 3 kJ (e) None of these. + 10 mA Part I- vent with values of statemen wer nt of pow the 12V i internal resistance Rm, and a series resistor Rm and RV compare? t best describes the power developed by er battery supplies 250A to the starter motor [11] The value of the voltage vab is: (a) -24 V (b) 22 V (c) -15V (d) 6V (e) None of these. + vo - 3vo 31 Ω 19 Ω 6 Ω1A + vab - [13] Find the voltage v. (a) 38 V (b) 110 V (c) -40 V (d) 240 V (e) None of these. 20 mA 16 kΩ 12 kΩ 12 kΩ 12 kΩ 8 kΩ + v - [14] The voltage vo is: (a) 3 V (b) -4 V (c) 0.75 V (d) 0 V (e) None of these 6 A 6 4 9 10 7 Ohms - vo +3 8 1 [9] The voltage and current in a circuit element have the polarities indicated below. Both quantities are zero for t < 0. For t ≥ 0 they have the form: V e10v t5−−= mA e3010i t10−+= What is the total energy delivered to the element? (a) 20 mJ (b) 60 mJ (c) -15 mJ (d) -40 mJ (e) None of these. i + v - [12] The variable resistors R1 and R2 can be adjusted over the range from 2Ω to 95Ω. If the minimum ammeter current is Imin and the maximum ammeter current is Imax, what is the sum Imin + Imax ? (a) 0.5 A (b) 6 A (c) 12 A (d) 13 A (e) None of these 12 A R1 R2 Ideal ammeter + - Answer key: 1c 2a 3c 4d 5b 6a 7b 8c 9d 10c 11a 12c 13b 14d 15c 16c
