41 Questions on General Physics 2 with Solution - Final Exam | PHYS 1120, Exams of Physics

Download 41 Questions on General Physics 2 with Solution - Final Exam | PHYS 1120 and more Exams Physics in PDF only on Docsity! PHYS1120 Fall 2013 Final Exam Version 0001 Name (print please) Sp (ud on ¥ Student ID Your TA’s Name & the Start Time of your recitation (Circle Each) 8am, 9am, 10am, llam, 12pm, Ipm, 2pm, 3pm, 4pm Sabrina David Andrea Egan Ben Chapman/Julian Giller Matthew Heinemann Ross Huton Timothy Livingston-Large Karl Mayer Joseph Samaniego-Evans Please DO NOT OPEN the Exam until you are told to. PLEASE READ carefully the fotlowing instructions and place a check in each box on the left as you complete or read the instructions, or you will automatically lose 10 points. } Make sure your seat number is correct. You must show your student [D card upon request Cc] Circle your TA’s name and recitation time above. LC] Print and Bubble in your Name and Student ID number on the bubble sheet. Print and Bubble in your exam version number (0001) in the upper left corner of the bubbie sheet. CJ Please leave the areas labeled Code and Date blank. | Erase mistakes on bubble sheets as thoroughly as possible. As you take the exam, show your work and circle the correct answers on your exam as well as mark them on the bubble sheet. Your final answer should be marked on your bubble sheet! By handing in this exam, you agree to the following statement: "I have read and followed the instructions above. On my honor, as a University of Colorado Student, I have neither given nor received unauthorized assistance on this work" Signature. @Your exam should have 18 pages including this front and two empty pages for notes. © This exam consists of 41 multiple-choice questions. We will drop one wrong answer, so you will be graded on 40 questions, at 2.5 points each, for a total of 100 points. Maximum points you can get is 100. © Allowed material: 2 pages of letter-sized equation sheet, #2 pencils, erasers and a calculator. © NO cellphones, headsets, scrap papers nor electronic devices except for a scientific calculator are allowed. If seen, it will be considered as an act of cheating. * Possibly useful information: c=3.0x 108 m/s lel=1.6x 101°C, Ke I/(4ne.)=9.0 x10°Nm?/C?, up= 40x 107 (SI unit) m, = 9.11 x 10% kg, m,= 1.67 x 1077 kg,@ Into the page @ Out of the page v.0001 uuul i 1. A coil of wire with N=1000 loops with radius 56.4 cm is attached to a resistor with R=10Q in the xy plane shown on right. The B field starts increasing from 0 to 1 T at a rate of 0.004 T/ sec in the +z direction. What is the power dissipated through the resistor while the B field is changing? nant, (A) 1.6 mW (B) oy ©4mw (DAW (E) 0 W (ie., no power dissipation occurs) 2. A very long solenoid with a circular cross section with n, = 100 turns/cm lies inside of a short outer coil with 25 turns, as shown on the left. The area of the solenoid is Ag = 0.01 m’ and the area of the outer coil Ac = 0.10m?. When the current of the solenoid is increasing from zero to 2.00 A over 50 ms, what is the magnitude of the EMF in the outer coil while the current is increasing? Mov) (B)13V (0.005 V ()0.05A — (B) None of these MOB ge cI L - Gio le 3. A beam of light travels from air into water. In air, the angle between the direction of the light beam and the normal to the surface of the water is 45 degrees. Which of the following statements are true? Note that the index of refraction of air isn, =1.00, and water n, = 1.33. oo Cf I. The speed of light decreases, when it enters the water. a ne Il. The frequency of the light decreases when it enters the wafer. IH. In the water, the angle between the light beam and the normal to the. surface is smaller than 45 degrees. (A) land (B) Land (OU and IE CMI and Uy (B) all are true rane V.0001 3 1 (A) The next two questions refer to the figure on the right. It shows the 10 time variation of the current through an electric clothes dryer when it is plugged into an AC outlet with 230 V rms, 50 Hz. tn -5| 9. What is the peak voltage of this outlet? reer. 16 (A)HSV (B)163V.— (©) 230 Orv) wav 10. What is the average power (ic. rms power) consumption of this dryer when it is connected to the 230 V rms, 50 Hz outlet? , a. (A) 3250 W (B) 2300 W © 1625W £D)1150W (ROW Naat 11. In class Professor Betterton did a demo with a transformer with a large number of coils N, connected to wall voltage (115 V, 60 Hz) coupled to a small number of coils N, connected to a pair of nails, When the nails were allowed to touch to complete the circuit, what happened and why? (A) The step-down transformer produced a low voltage and low current flowing through the nails, causing aes happen to the nails. step-down transformer produced a decreased voltage and increased current flowing through the nails, (or power dissipation which made the nails heat up and melt together. (C) The step-up transformer produced a high voltage and high current flowing through the nails, causing the nails to spark continuously. (D) The step-up transformer produced a high voltage and low current flowing through the nails, causing the nails to act as a high-voltage source. V.G001 6 12.Three ideal polarizers, labeled 1, 2, and 3, are placed between a source of unpolarized light and an observer as shown below. As shown, the transmission axes of the three filters are at angles of 0, 45, and 90 degrees, respectively, relative to the vertical. How much light does the observer view coming through all three filters? tremoves = ~ i¢ light source (unpolarized) polarizer 1 2 3 observer pent when filter 2 is present and some light when filter 2 is removed. (®) Some light when filter 2 is present and no light when filter 2 is removed. (C) No light when filter 2 is present and still no light when filter 2 is removed. (D) Some light when filter 2 is present and more light when filter 2 is removed. (E) Some light when 2 is present and the same amount of light when filter 2 is removed. 13. A beam of light traveling in an unknown medium is found to undergo total internal reflection at the boundary of the medium and air (n, =1), as air shown on the right. The angle between the light beam and normal to the ned boundary with the air is 9 = 30 degrees. What is the refractive index of this medium, #,? [Note: 6 is not necessarily the critical angle. ] — eo . hh a a (A) <1 tn ordeal Ro Par Q__ (B) isn,<15 refis hee *, ) Ge > @e E) ‘Impossible to determine from the information given 4 ena Se Gi, , ( . { Ay 12 Fy Ry } he V.0001 7 14. Which of the following correctly describes the image formed by the lens in the figure below? object (A) Real, non-inverted (B) Real, inverted | | ey "Virtual, ne non-iny wetted ~e conn ne BBs nce ea pec ns en nnn ne o- f (D) Virtual, inverted (E) No image is formed 15. A camera is focused on an object. The object is imaged on the film, which is 3.0 cm to the right of the camera lens. What can you say about the focal length f of the lens? oo — Cay < 300m.) oS ail . = 31 object “4 (C)f>3.0cm 3.0cm t : wy 7 So ae Tt (D) There is not enough information to say anything about f. 16. In the figure below, the position of a wire of loop is shown at ¢, and ty+At. The loop starts from rest in each case and is displaced to the right in Case A and to the left in Case B. Which of the following statements are true ? III. In both cases, the direction of the induced trent in the oop i is 5 the same. TV. In both bases, the sign of the magnetic flux due to the induced current is the same. et, K { () Land _ “ay “Ti and I Case A side view : side view (C) 1 WandIv t t=t, =ty _ . (D) H, Mand Iv . (©) Wand Iv é 5 : 3 side view... ..... side view . at t=t tt at t=tytAt V.0001 8 25. The picture above shows three different charge distributions on two very large, parallel metal plates. The picture only shows a smali portion near the center of the two plates, so you can neglect fringing effects at the edges of the plates. The charge per unit area is 6). Which of the depicted charge distributions are physically correct for the situation described above ? — | | (Excess charge is evenly (Excess charge is on B disiributed on both sides) |C inside surfaces) 7 5 {A)A (B)B (ore A (D)Neither of above is correct (E) Impossible to tell from the information given (Excess charge is on outside surfaces) 26. The picture on the right shows the equipotential lines of two charges, labeled 1 and 2. Which of the following statements is/are correct? 40V = “ Ckarge 2 has a larger magnitude than charge |. . U,'If a proton were to be released from the point labeled “X it would feel a net force to the right. left<€ > Right WIE~The two charges 1 and 2 repel each other. —, far } (B) Tand II (C) Tand (D)H and I (E) All are false. Qe V.0601 ie 23. A small positive charge +q initially sits at a distance 4R from a large stationary charge -Q. The small charge (+q) is released from the rest at t = 0. The only force on the small charge is the electrostatic force from the large charge. After the charge +q has traveled a distance 3R, and is now a distance R from the large charge, what is its kinetic energy? 0 Location att= 3R +q Location @ < @ att=0 C2K24 Ap K2d None of these aR QR 24. Two large conducting plates are placed paraltel to each other a distance D apart and are connected by wires to Box X, which contains an unknown circuit Box X element as shown. It is observed that, as the plates are moved farther apart, the non-zero electric field between the plates decreases. Which of the following circuit elements does the box X contain? | | i { 1 = ¢ - T (A) -_ (B) () (dD) plates moved sees) resistor wire open switch apart D 27. An ohm-meter measures the resistance between points a and b in the arrangement of 4 resistors shown. All four resistors are identical, a with R = 3.0 Q. What is the measured resistance between a and b? we ms \ (A102 (B)30Q2 C40 2 {602 Roa N, a b The following two questions refer to a copper cylinder machined in a shape shown below. The ends are connected to a battery so that a current flows through the copper. 28. Which region has the greatest current ? “, (AA (B)B cc *.(D) All three are the same a nnn 29, Which regign-has'the greatest electric field ? (AJA (@)B } «jc (D) AH three are the same ned 30. In the circuit shown at right, how much power is dissipated in the 5Q resistor ? a sy (A)O W (B) 1 W (© SW } (D) 9.5 W () 10 W a“ a V.0081 13 | | | { | i I { I { 1 1 } : i ' i i { i { { | | i | { f i | i | | { i | t } } { i i 37. The figure on the right shows a rectangular area with sides a and b, with a homogeneous magnetic field out of the page. The magnitude of this field inside the area is B. The field is zero everywhere else. What is the magnitude of the flux through the dashed circular area of radius r shown on the right? ln j ‘. \/ (Ayo (B)B (C)Bab | 3 @) Baar (E) Bar? SS 5 - a Y OOO OOO OO (ORORO) Region I Region II ®@®@® ® @} ® @ ® B/@ 882888 Sle ob o ® 8 8 8/8 38. Five loops are made of copper wire of the same cross- sectional area. Loops 1-4 are identical; loop 5 has the same height as the others but is longer. At the instant shown, all the loops are moving at the same speed (v) in the directions indicated, There is a uniform magnetic field pointing into the page in region 1, there is no magnetic field in region II. ignore any interactions between the loops. Which of the following correctly ranks the magnitude of the current in the loops? (A)1,> I> 1,> 1, > Is Bi> => h> Is OL> b= @)L> TIS =I, [roe enc atte en ne eene amen eunene nme V.0001 18 39. A coaxial cable consists of an inner solid wire with radius R and | an outer cylindrical wire with inner radius 2R and outer radius 3R. Cat oF The inner wire carries total current J, #aée-the page and the outer Meee cylindrical wire carries current /, oatefthe page, where J, > J, . Both i wires have uniform current density. What is the magnitude of the : magnetic field B atr = 3.5 R? S wy ) A) Ze B po(Ti + I2) (Goold = b) py Mofile E) N th : (A) Zero @B) aR (C) "aR y, (D) oaR (E) None of these Axis of rotation 40. A loop carrying current I is placed in a uniform B field as shown on the pl right. What is the direction of the torque on the current loop about the axis B of rotation indicated ? “G oO OF M> (© t) i iy 7 v 41. Two infinitely long wires 1 and 2 carry the same current J in the ty direction. 2 + The wires are in the xy plane, as shown on the right. What is the direction of the force y acting on wire 1? -@—>"* +27 a (A) +y fe) +x (C) -x (D) +z @)-z a NS i, ranma 47